Production method for fluoropolymer, surfactant for polymerization, and use of surfactant

ABSTRACT

A composition including a fluoropolymer and substantially free from a compound represented by the following formula (3): (H—(CF 2 ) 8 —SO 3 ) q M 2 , wherein M 2  is H, a metal atom, NR 5   4 , imidazolium optionally containing a substituent, pyridinium optionally containing a substituent, or phosphonium optionally containing a substituent; R 5 s are each H or an organic group and are the same as or different from each other; and q is 1 or 2.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Rule 53(b) Divisional of U.S. application Ser. No.16/499,047 filed Sep. 27, 2019, which is a National Stage ofInternational Application No. PCT/JP2018/013620 filed Mar. 30, 2018,claiming priority based on Japanese Patent Application No. 2017-073084filed Mar. 31, 2017, Japanese Patent Application No. 2017-248552 filedDec. 25, 2017 and Japanese Patent Application No. 2018-020462 filed Feb.7, 2018, the above-noted applications incorporated herein by referencein their respective entireties.

TECHNICAL FIELD

The invention relates to methods for producing a fluoropolymer. Theinvention also relates to surfactants for polymerization. The inventionalso relates to use of a surfactant for production of a fluoropolymer.

BACKGROUND ART

Fluorinated anionic surfactants are used in production of fluoropolymersby emulsion polymerization. The use of hydrocarbon surfactants has alsobeen recently proposed instead of the use of fluorinated anionicsurfactants.

For example, Patent Literature 1 discloses a semi-batch emulsionpolymerization process for the production of a fluoroelastomer, thefluoroelastomer having at least 58 weight percent fluorine, including:(a) charging a reactor with a quantity of an aqueous solutionsubstantially free of surfactant; (B) charging the reactor with aquantity of a monomer mixture containing i) from 25 to 75 weightpercent, based on total weight of the monomer mixture, of a firstmonomer, the first monomer selected from the group consisting ofvinylidene fluoride and tetrafluoroethylene, and ii) between 75 and 25weight percent, based on total weight of the monomer mixture, of one ormore additional copolymerizable monomers, different from the firstmonomer, wherein the additional monomer is selected from the groupconsisting of fluorine-containing olefins, fluorine-containing vinylethers, hydrocarbon olefins and mixtures thereof; (c) initiatingpolymerization to form a fluoroelastomer dispersion while maintainingthe reaction medium at a pH between 1 and 7, at a pressure between 0.5and 10 MPa, and at a temperature between 25° C. and 130° C.; and (D)charging the reactor, after polymerization has begun, with a quantity ofa hydrocarbon anionic surfactant of the formula R-L-M wherein R is analkyl group having between 6 and 17 carbon atoms, L is selected from thegroup consisting of —ArSO₃—, —SO₃—, —SO₄—, —PO₃—, and —COO— and M is aunivalent cation.

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2010-511096 T

SUMMARY OF INVENTION Technical Problem

The invention aims to provide a novel method for producing afluoropolymer.

Solution to Problem

The invention relates to a method for producing a fluoropolymerincluding

polymerizing a fluoromonomer in an aqueous medium in the presence of asurfactant to provide a fluoropolymer,

the surfactant including at least one selected from the group consistingof:

a surfactant (a) represented by the following formula (a):

wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group;

R^(1a), R^(2a), and R^(3a) contain five or more carbon atoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a)s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring; and

a surfactant (b) represented by the following formula (b):

wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C10 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom,NR^(5b) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to A^(b) in the formula.

In the formula (a), R^(2a) and R^(3a) are each preferably individually asingle bond, a linear or branched alkylene group containing one or morecarbon atoms, or a cyclic alkylene group containing three or more carbonatoms, with a hydrogen atom that binds to a carbon atom being optionallyreplaced by a hydroxy group or a monovalent organic group that containsan ester bond.

In the formula (a), R^(1a) is preferably a C1-C8 linear or branchedalkyl group free from a carbonyl group, a C3-C8 cyclic alkyl group freefrom a carbonyl group, a C2-C45 linear or branched alkyl groupcontaining 1 to 10 carbonyl groups, a C3-C45 cyclic alkyl groupcontaining a carbonyl group, or a C3-C45 alkyl group containing amonovalent or divalent heterocycle.

In the formula (a), R^(1a) is preferably a group represented by thefollowing formula:

wherein n^(11a) is an integer of 0 to 10; R^(11a) is a C1-C5 linear orbranched alkyl group or a C3-C5 cyclic alkyl group; R^(12a) is a C0-C3alkylene group; and when n^(11a) is an integer of 2 to 10, R^(12a)s arethe same as or different from each other.

In the formula (a), R^(2a) and R^(3a) are each preferably individuallyan alkylene group free from a carbonyl group and containing one or morecarbon atoms.

In the formula (a), R^(2a) and R^(3a) are each preferably individually aC1-C3 alkylene group free from a carbonyl group.

In the formula (a), X^(a) is preferably NH₄.

In the formula (b), a sum of n, p, and q is preferably 6 or greater.

In the formula (b), R^(1b) is preferably a methyl group.

In the formula (b), X^(b) is preferably a metal atom or NR^(5b) ₄,wherein R^(5b) is defined as described above.

the surfactant preferably has a ¹H-NMR spectrum in which all peakintensities observed in a chemical shift range of 2.0 to 5.0 ppm give anintegral of 10 or higher.

The invention relates to a surfactant for polymerization, containing atleast one selected from the group consisting of:

a surfactant (a) represented by the following formula (a):

wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group;

R^(1a), R^(2a), and R^(3a) contain five or more carbon atoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a)s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring; and

a surfactant (b) represented by the following formula (b):

wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C00 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom,NR^(5b) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to A^(b) in the formula.

The invention relates to use of a surfactant for production of afluoropolymer by polymerizing a fluoromonomer in an aqueous medium,

the surfactant including at least one selected from the group consistingof:

a surfactant (a) represented by the following formula (a):

wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group;

R^(1a), R^(2a), and R^(3a) contain five or more carbon atoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a)s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring; and

a surfactant (b) represented by the following formula (b):

wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C10 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom,NR^(5b) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to A^(b) in the formula.

The invention relates to a composition containing

a fluoropolymer, and

at least one surfactant selected from the group consisting of:

a surfactant (a) represented by the following formula (a):

wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group;

R^(1a), R^(2a), and R^(3a) contain five or more carbon atoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a)s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring; and

a surfactant (b) represented by the following formula (b):

wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C10 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom,NR^(5b) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to A^(b) in the formula.

The invention relates to a composition containing a fluoropolymer andsubstantially free from a compound represented by the following formula(3):

(H—(CF₂)₈—SO₃)_(q)M²,

wherein M² is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and q is1 or 2.

In the composition of the invention, the compound represented by theformula (3) is preferably in an amount of 1000 ppb or less, morepreferably 25 ppb or less, relative to the fluoropolymer.

In an embodiment of the invention, the composition further contains acompound represented by the following formula (4) in an amount of 100ppb or more relative to the fluoropolymer,

the formula (4) being (H—(CF₂)₇—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition further contains acompound represented by the formula (4) in an amount of 100 ppb or morerelative to the fluoropolymer; and/or a compound represented by thefollowing formula (4′) in an amount of 100 ppb or more relative to thefluoropolymer,

the formula (4′) being (H—(CF₂)₈—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition further contains acompound represented by the following formula (5) in an amount of 100ppb or more relative to the fluoropolymer,

the formula (5) being (H—(CF₂)₁₃—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition further contains acompound represented by the formula (5) in an amount of 100 ppb or morerelative to the fluoropolymer; and/or a compound represented by thefollowing formula (5′) in an amount of 100 ppb or more relative to thefluoropolymer,

the formula (5′) being (H—(CF₂)₁₄—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In these embodiments of the invention, the composition is in the form ofan aqueous dispersion.

In an embodiment of the invention, the composition further contains acompound represented by the formula (4) in an amount of 1000 ppb or lessrelative to the fluoropolymer; and 1% by mass or more of a nonionicsurfactant. In an embodiment of the invention, the composition furthercontains at least one of a compound represented by the formula (4) or acompound represented by the formula (4′), with the compound representedby the formula (4) being in an amount of 1000 ppb or less relative tothe fluoropolymer and with the compound represented by the formula (4′)being in an amount of 1000 ppb or less relative to the fluoropolymer;and 1% by mass or more of a nonionic surfactant. In an embodiment of theinvention, the composition further contains a compound represented bythe formula (5) in an amount of 1000 ppb or less relative to thefluoropolymer; and 1% by mass or more of a nonionic surfactant. In anembodiment of the invention, the composition further contains at leastone of a compound represented by the formula (5) or a compoundrepresented by the formula (5′), with the compound represented by theformula (5) being in an amount of 1000 ppb or less relative to thefluoropolymer and with the compound represented by the formula (5′)being in an amount of 1000 ppb or less relative to the fluoropolymer;and 1% by mass or more of a nonionic surfactant.

In an embodiment of the invention, the composition further contains acompound represented by the formula (4) in an amount of 1000 ppb or lessrelative to the fluoropolymer. In an embodiment of the invention, thecomposition further contains at least one of a compound represented bythe formula (4) or a compound represented by the formula (4′), with thecompound represented by the formula (4) being in an amount of 1000 ppbor less relative to the fluoropolymer and with the compound representedby the formula (4′) being in an amount of 1000 ppb or less relative tothe fluoropolymer. In an embodiment of the invention, the compositionfurther contains a compound represented by the formula (5) in an amountof 1000 ppb or less relative to the fluoropolymer. In an embodiment ofthe invention, the composition further contains at least one of acompound represented by the formula (5) or a compound represented by theformula (5′), with the compound represented by the formula (5) being inan amount of 1000 ppb or less relative to the fluoropolymer and with thecompound represented by the formula (5′) being in an amount of 1000 ppbor less relative to the fluoropolymer.

In an embodiment of the invention, the composition further contains acompound represented by the formula (4) in an amount of 100 ppb or lessrelative to the fluoropolymer. In an embodiment of the invention, thecomposition further contains at least one of a compound represented bythe formula (4) or a compound represented by the formula (4′), with thecompound represented by the formula (4) being in an amount of 100 ppb orless relative to the fluoropolymer and with the compound represented bythe formula (4′) being in an amount of 100 ppb or less relative to thefluoropolymer. In an embodiment of the invention, the compositionfurther contains a compound represented by the formula (5) in an amountof 100 ppb or less relative to the fluoropolymer. In an embodiment ofthe invention, the composition further contains at least one of acompound represented by the formula (5) or a compound represented by thefollowing formula (5′), with the compound represented by the formula (5)being in an amount of 100 ppb or less relative to the fluoropolymer andwith the compound represented by the formula (5′) being in an amount of100 ppb or less relative to the fluoropolymer. In these embodiments ofthe invention, the composition is in the form of powder.

In the composition of the invention, the fluoropolymer is preferablyobtained by polymerization using a hydrocarbon-based surfactant.

The composition preferably has a tone L* of 50 or lower after firing andbefore a fluorine treatment.

The composition preferably exhibits a tone change ΔL* of 70% or higherbefore and after a fluorination treatment.

The invention also relates to a molded article containing the abovecomposition.

The molded article of the invention is preferably a stretched article.

Advantageous Effects of Invention

The production method of the invention is a novel method for producing afluoropolymer.

The production method of the invention includes polymerization in thepresence of the above surfactant, and thus can produce a fluoropolymerhaving a high molecular weight and allows the surfactant to be lesslikely to remain in the resulting fluoropolymer.

DESCRIPTION OF EMBODIMENTS

Before the specific description of the invention, some terms used in thedescription are defined or described below.

The fluororesin as used herein means a partially crystallinefluoropolymer which is a fluoroplastic. The fluororesin has a meltingpoint and has thermoplasticity, and may be either melt-fabricable or nonmelt-processible.

The melt-fabricable as used herein means an ability of a polymer to beprocessed in a molten state using a conventional processing device suchas an extruder or an injection molding machine. Thus, a melt-fabricablefluororesin usually has a melt flow rate of 0.01 to 500 g/10 minmeasured by a measurement method to be described later.

The fluoroelastomer as used herein means an amorphous fluoropolymer. Theterm “amorphous” means that a fluoropolymer has a melting peak (ΔH) of4.5 J/g or lower determined by differential scanning calorimetry (DSC)(temperature-increasing rate: 10° C./min) or differential thermalanalysis (DTA) (temperature-increasing rate: 10° C./min). Thefluoroelastomer is to crosslink to exhibit elastomeric behavior. Theelastomeric behavior means an ability of a polymer to be stretched andto maintain its original length when the force required to stretch thepolymer is no longer applied.

The partially fluorinated elastomer as used herein means a fluoropolymercontaining a fluoromonomer unit, containing a perfluoromonomer unit inan amount of less than 90 mol % of all polymerized units, having a glasstransition temperature of 20° C. or lower, and having a melting peak(ΔH) of 4.5 J/g or lower.

The perfluoroelastomer as used herein means a fluoropolymer containing aperfluoromonomer unit in an amount of 90 mol % or more of allpolymerized units, having a glass transition temperature of 20° C. orlower, having a melting peak (ΔH) of 4.5 J/g or lower, and having afluorine atom concentration in the fluoropolymer of 71% by mass or more.The fluorine atom concentration in the fluoropolymer as used herein isthe concentration (% by mass) of the fluorine atoms contained in thefluoropolymer calculated based on the types and amounts of the monomersconstituting the fluoropolymer.

The perfluoromonomer as used herein means a monomer free from acarbon-hydrogen bond in the molecule. The perfluoromonomer may be amonomer which contains carbon atoms and fluorine atoms and in which somefluorine atoms binding to any of the carbon atoms are replaced bychlorine atoms, and may be a monomer containing a nitrogen atom, anoxygen atom, a sulfur atom, a phosphorus atom, a boron atom, or asilicon atom in addition to the carbon atoms. The perfluoromonomer ispreferably a monomer in which all hydrogen atoms are replaced byfluorine atoms. The perfluoromonomer does not encompass a monomer givinga crosslinking site.

The monomer giving a crosslinking site is a monomer (cure-site monomer)containing a crosslinkable group that can give a fluoropolymer acrosslinking site to form a crosslink with the use of a curing agent.

The polytetrafluoroethylene (PTFE) as used herein is preferably afluoropolymer in which tetrafluoroethylene represents 99 mol % or moreof all polymerized units.

The fluororesin other than polytetrafluoroethylene and thefluoroelastomer as used herein are each preferably a fluoropolymer inwhich tetrafluoroethylene represents less than 99 mol % of allpolymerized units.

The amounts of the respective monomers constituting the fluoropolymercan be calculated by any appropriate combination of NMR, FT-IR,elemental analysis, and X-ray fluorescence analysis in accordance withthe types of the monomers.

The term “organic group” as used herein means a group containing one ormore carbon atoms or a group obtainable by removing one hydrogen atomfrom an organic compound.

Examples of the “organic group” include:

an alkyl group optionally containing one or more substituents,

an alkenyl group optionally containing one or more substituents,

an alkynyl group optionally containing one or more substituents,

a cycloalkyl group optionally containing one or more substituents,

a cycloalkenyl group optionally containing one or more substituents,

a cycloalkadienyl group optionally containing one or more substituents,

an aryl group optionally containing one or more substituents,

an aralkyl group optionally containing one or more substituents,

a non-aromatic heterocyclic group optionally containing one or moresubstituents,

a heteroaryl group optionally containing one or more substituents,

a cyano group,

a formyl group,

RaO—,

RaCO—,

RaSO₂—,

RaCOO—,

RaNRaCO—,

RaCONRa—,

RaOCO—,

RaOSO₂—, and

RaNRbSO₂—,

wherein each Ra is independently

an alkyl group optionally containing one or more substituents,

an alkenyl group optionally containing one or more substituents,

an alkynyl group optionally containing one or more substituents,

a cycloalkyl group optionally containing one or more substituents,

a cycloalkenyl group optionally containing one or more substituents,

a cycloalkadienyl group optionally containing one or more substituents,

an aryl group optionally containing one or more substituents,

an aralkyl group optionally containing one or more substituents,

a non-aromatic heterocyclic group optionally containing one or moresubstituents, or

a heteroaryl group optionally containing one or more substituents, and

each Rb is independently H or an alkyl group optionally containing oneor more substituents.

The organic group is preferably an alkyl group optionally containing oneor more substituents.

The term “substituent” as used herein means a group which can replaceanother atom or group. Examples of the “substituent” include analiphatic group, an aromatic group, a heterocyclic group, an acyl group,an acyloxy group, an acylamino group, an aliphatic oxy group, anaromatic oxy group, a heterocyclic oxy group, an aliphatic oxycarbonylgroup, an aromatic oxycarbonyl group, a heterocyclic oxycarbonyl group,a carbamoyl group, an aliphatic sulfonyl group, an aromatic sulfonylgroup, a heterocyclic sulfonyl group, an aliphatic sulfonyloxy group, anaromatic sulfonyloxy group, a heterocyclic sulfonyloxy group, asulfamoyl group, an aliphatic sulfonamide group, an aromatic sulfonamidegroup, a heterocyclic sulfonamide group, an amino group, an aliphaticamino group, an aromatic amino group, a heterocyclic amino group, analiphatic oxycarbonylamino group, an aromatic oxycarbonylamino group, aheterocyclic oxycarbonylamino group, an aliphatic sulfinyl group, anaromatic sulfinyl group, an aliphatic thio group, an aromatic thiogroup, a hydroxy group, a cyano group, a sulfo group, a carboxy group,an aliphatic oxyamino group, an aromatic oxyamino group, acarbamoylamino group, a sulfamoyl amino group, a halogen atom, asulfamoyl carbamoyl group, a carbamoyl sulfamoyl group, a dialiphaticoxyphosphinyl group, and a diaromatic oxyphosphinyl group.

In the description, the numerical ranges expressed by the endpoints eachinclude all numbers within the range (for example, the range of 1 to 10includes 1.4, 1.9, 2.33, 5.75, 9.98, and the like).

The phrase “at least one” as used herein includes all numbers equal toor greater than 1 (e.g., at least 2, at least 4, at least 6, at least 8,at least 10, at least 25, at least 50, at least 100, and the like).

The invention will be specifically described hereinbelow.

The production method of the invention is a method for producing afluoropolymer including polymerizing a fluoromonomer in an aqueousmedium in the presence of a surfactant to provide a fluoropolymer, thesurfactant used therein including at least one surfactant (hereinafter,also referred to as a surfactant (1)) selected from the group consistingof:

a surfactant (a) represented by the following formula (a):

(wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group;

R^(1a), R^(2a), and R^(3a) contain five or more carbon atoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a)s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring); and

a surfactant (b) represented by the following formula (b):

(wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C10 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

Ab is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom, NR^(5b)₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to A^(b) in the formula).

The surfactant (a) is described below.

In the formula (a), R^(1a) is a linear or branched alkyl groupcontaining one or more carbon atoms or a cyclic alkyl group containingthree or more carbon atoms.

When containing three or more carbon atoms, the alkyl group mayoptionally contain a carbonyl group (—C(═O)—) between two carbon atoms.When containing two or more carbon atoms, the alkyl group may optionallycontain a carbonyl group at an end of the alkyl group. In other words,acyl groups such as an acetyl group represented by CH₃—C(═O)— are alsoincluded in the alkyl group.

When containing three or more carbon atoms, the alkyl group mayoptionally contain a monovalent or divalent heterocycle, or mayoptionally form a cycle. The heterocycle is preferably an unsaturatedheterocycle, more preferably an oxygen-containing unsaturatedheterocycle, and may be a furan ring, for example. In R^(1a), a divalentheterocycle may be present between two carbon atoms, or a divalentheterocycle may be present at an end and bind to —C(═O)—, or amonovalent heterocycle may be present at an end of the alkyl group.

The “number of carbon atoms” in the alkyl group herein includes thenumber of carbon atoms constituting the carbonyl groups and the numberof carbon atoms constituting the heterocycles. For example, the numberof carbon atoms in the group represented by CH₃—C(═O)—CH₂— is 3, thenumber of carbon atoms in the group represented byCH₃—C(═O)—C₂H₄—C(═O)—C₂H₄— is 7, and the number of carbon atoms in thegroup represented by CH₃—C(═O)— is 2.

In the alkyl group, a hydrogen atom that binds to a carbon atom mayoptionally be replaced by a functional group such as a hydroxy group(—OH) or a monovalent organic group containing an ester bond. Still, itis preferably not replaced by any functional group.

An example of the monovalent organic group containing an ester bond is agroup represented by the formula: —O—C(═O)—R^(101a), wherein R^(101a) isan alkyl group.

In the alkyl group, 75% or less of the hydrogen atoms binding to any ofthe carbon atoms may be replaced by halogen atoms, 50% or less thereofmay be replaced by halogen atoms, or 25% or less thereof may be replacedby halogen atoms. The alkyl group is preferably a non-halogenated alkylgroup containing no halogen atoms such as fluorine atoms and chlorineatoms.

In the formula (a), R^(2a) and R^(3a) are each individually a singlebond or a divalent linking group.

Preferably, R^(2a) and R^(3a) are each individually a single bond, alinear or branched alkylene group containing one or more carbon atoms,or a cyclic alkylene group containing three or more carbon atoms.

The alkylene group constituting R^(2a) and R^(3a) is preferably freefrom a carbonyl group.

In the alkylene group, a hydrogen atom that binds to a carbon atom mayoptionally be replaced by a functional group such as a hydroxy group(—OH) or a monovalent organic group containing an ester bond. Still, itis preferably not replaced by any functional group. An example of themonovalent organic group containing an ester bond is a group representedby the formula: —O—C(═O)—R^(102a), wherein R^(102a) is an alkyl group.In the alkylene group, 75% or less of the hydrogen atoms binding to anyof the carbon atoms may be replaced by halogen atoms, 50% or lessthereof may be replaced by halogen atoms, or 25% or less thereof may bereplaced by halogen atoms. The alkylene group is preferably anon-halogenated alkylene group containing no halogen atoms such asfluorine atoms and chlorine atoms.

R^(1a), R^(2a), and R^(3a) contain 5 or more carbon atoms in total. Thetotal number of carbon atoms is preferably 7 or greater, more preferably9 or greater, while preferably 20 or smaller, more preferably 18 orsmaller, still more preferably 15 or smaller.

Any two of R^(1a), R^(2a), and R^(3a) may optionally bind to each otherto form a ring.

In the formula (a), A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H,a metal atom, NR^(4a) ₄, imidazolium optionally containing asubstituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent, wherein R^(4a) s areeach H or an organic group, and are the same as or different from eachother. R^(4a) is preferably H or a C1-C10 organic group, more preferablyH or a C1-C4 organic group. Examples of the metal atom include alkalimetals (Group 1) and alkaline earth metals (Group 2), and preferred isNa, K, or Li.

X^(a) is preferably H, an alkali metal (Group 1), an alkaline earthmetal (Group 2), or NR^(4a) ₄, more preferably H, Na, K, Li, or NH₄because they are easily dissolved in water, still more preferably Na, K,or NH₄ because they are more easily dissolved in water, particularlypreferably Na or NH₄, most preferably NH₄ because it can be easilyremoved. When X^(a) is NH₄, the surfactant can have excellent solubilityin an aqueous medium and the metal component is less likely to remain inthe fluoropolymer or the final product.

R^(1a) is preferably a C1-C8 linear or branched alkyl group free from acarbonyl group, a C3-C8 cyclic alkyl group free from a carbonyl group, aC2-C45 linear or branched alkyl group containing 1 to 10 carbonylgroups, a C3-C45 cyclic alkyl group containing a carbonyl group, or aC3-C45 alkyl group containing a monovalent or divalent heterocycle.

R^(1a) is more preferably a group represented by the following formula:

wherein n^(11a) is an integer of 0 to 10; R^(11a) is a C1-C5 linear orbranched alkyl group or a C3-C5 cyclic alkyl group; R^(12a) is a C0-C3alkylene group; and when n^(11a) is an integer of 2 to 10, R^(12a)s arethe same as or different from each other.

In the formula, n^(11a) is preferably an integer of 0 to 5, morepreferably an integer of 0 to 3, still more preferably an integer of 1to 3.

The alkyl group for R^(11a) is preferably free from a carbonyl group.

In the alkyl group for R^(11a), a hydrogen atom that binds to a carbonatom may optionally be replaced by a functional group such as a hydroxygroup (—OH) or a monovalent organic group containing an ester bond.Still, it is preferably not replaced by any functional group.

An example of the monovalent organic group containing an ester bond is agroup represented by the formula: —O—C(═O)—R^(103a), wherein R^(103a) isan alkyl group.

In the alkyl group for R^(11a), 75% or less of the hydrogen atomsbinding to any of the carbon atoms may be replaced by halogen atoms, 50%or less thereof may be replaced by halogen atoms, or 25% or less thereofmay be replaced by halogen atoms. The alkyl group is preferably anon-halogenated alkyl group containing no halogen atoms such as fluorineatoms and chlorine atoms.

R^(12a) is a C0-C3 alkylene group. The number of carbon atoms ispreferably 1 to 3. The alkylene group for R^(12a) may be either linearor branched.

The alkylene group for R^(12a) is preferably free from a carbonyl group.R^(12a) is more preferably an ethylene group (—C₂H₄—) or a propylenegroup (—C₃H₆—).

In the alkylene group for R^(12a), a hydrogen atom that binds to acarbon atom may optionally be replaced by a functional group such as ahydroxy group (—OH) or a monovalent organic group containing an esterbond. Still, it is preferably not replaced by any functional group.

An example of the monovalent organic group containing an ester bond is agroup represented by the formula: —O—C(═O)—R^(104a), wherein R^(104a) isan alkyl group.

In the alkylene group for R^(12a), 75% or less of the hydrogen atomsbinding to any of the carbon atoms may be replaced by halogen atoms, 50%or less thereof may be replaced by halogen atoms, or 25% or less thereofmay be replaced by halogen atoms. The alkylene group is preferably anon-halogenated alkylene group containing no halogen atoms such asfluorine atoms and chlorine atoms.

R^(2a) and R^(3a) are preferably each individually an alkylene groupfree from a carbonyl group and containing one or more carbon atoms, morepreferably a C1-C3 alkylene group free from a carbonyl group, still morepreferably an ethylene group (—C₂H₄—) or a propylene group (—C₃H₆—).

Next, the surfactant (b) is described below.

In the formula (b), R^(1b) is a linear or branched alkyl groupcontaining one or more carbon atoms and optionally containing asubstituent or a cyclic alkyl group containing three or more carbonatoms and optionally containing a substituent.

When containing three or more carbon atoms, the alkyl group mayoptionally contain a monovalent or divalent heterocycle, or mayoptionally form a cycle. The heterocycle is preferably an unsaturatedheterocycle, more preferably an oxygen-containing unsaturatedheterocycle, and may be a furan ring, for example. In R^(1b), a divalentheterocycle may be present between two carbon atoms, or a divalentheterocycle may be present at an end and bind to —C(═O)—, or amonovalent heterocycle may be present at an end of the alkyl group.

The “number of carbon atoms” in the alkyl group herein includes thenumber of carbon atoms constituting the heterocycles.

The substituent which may be contained in the alkyl group for R^(1b) ispreferably a halogen atom, a C1-C10 linear or branched alkyl group, aC3-C10 cyclic alkyl group, or a hydroxy group, particularly preferably amethyl group or an ethyl group.

The alkyl group for R^(1b) is preferably free from a carbonyl group.

In the alkyl group, 75% or less of the hydrogen atoms binding to any ofthe carbon atoms may be replaced by halogen atoms, 50% or less thereofmay be replaced by halogen atoms, or 25% or less thereof may be replacedby halogen atoms. The alkyl group is preferably a non-halogenated alkylgroup containing no halogen atoms such as fluorine atoms and chlorineatoms.

The alkyl group preferably contains no substituent.

R^(1b) is preferably a C1-C10 linear or branched alkyl group optionallycontaining a substituent or a C3-C10 cyclic alkyl group optionallycontaining a substituent, more preferably a C1-C10 linear or branchedalkyl group free from a carbonyl group or a C3-C10 cyclic alkyl groupfree from a carbonyl group, still more preferably a C1-C10 linear orbranched alkyl group free from a substituent, further more preferably aC1-C3 linear or branched alkyl group free from a substituent,particularly preferably a methyl group (—CH₃) or an ethyl group (—C₂H₅),most preferably a methyl group (—CH₃).

In the formula (b), R^(2b) and R^(4b) are each individually H or asubstituent; multiple R^(2b)s may be the same as or different from eachother and multiple R^(4b)s may be the same as or different from eachother.

The substituent for each of R^(2b) and R^(4b) is preferably a halogenatom, a C1-C10 linear or branched alkyl group, a C3-C10 cyclic alkylgroup, or a hydroxy group, particularly preferably a methyl group or anethyl group.

The alkyl group for each of R^(2b) and R^(4b) is preferably free from acarbonyl group. In the alkyl group, 75% or less of the hydrogen atomsbinding to any of the carbon atoms may be replaced by halogen atoms, 50%or less thereof may be replaced by halogen atoms, or 25% or less thereofmay be replaced by halogen atoms. The alkyl group is preferably anon-halogenated alkyl group containing no halogen atoms such as fluorineatoms and chlorine atoms.

The alkyl group preferably contains no substituent.

The alkyl group for each of R^(2b) and R^(4b) is preferably a C1-C10linear or branched alkyl group free from a carbonyl group or a C3-C10cyclic alkyl group free from a carbonyl group, more preferably a C1-C10linear or branched alkyl group free from a carbonyl group, still morepreferably a C1-C3 linear or branched alkyl group free from asubstituent, particularly preferably a methyl group (—CH₃) or an ethylgroup (—C2H5).

R^(2b) and R^(4b) are preferably each individually H or a C1-C10 linearor branched alkyl group free from a carbonyl group, more preferably H ora C1-C3 linear or branched alkyl group free from a substituent, stillmore preferably H, a methyl group (—CH₃), or an ethyl group (—C₂H₅),particularly preferably H.

In the formula (b), R^(3b) is a C1-C10 alkylene group optionallycontaining a substituent; when multiple R^(3b)s are present, they may bethe same as or different from each other.

The alkylene group is preferably free from a carbonyl group.

In the alkylene group, 75% or less of the hydrogen atoms binding to anyof the carbon atoms may be replaced by halogen atoms, 50% or lessthereof may be replaced by halogen atoms, or 25% or less thereof may bereplaced by halogen atoms. The alkylene group is preferably anon-halogenated alkyl group containing no halogen atoms such as fluorineatoms and chlorine atoms.

The alkylene group preferably contains no substituent.

The alkylene group is preferably a C1-C10 linear or branched alkylenegroup optionally containing a substituent or a C3-C10 cyclic alkylenegroup optionally containing a substituent, preferably a C1-C10 linear orbranched alkylene group free from a carbonyl group or a C3-C10 cyclicalkylene group free from a carbonyl group, more preferably a C1-C10linear or branched alkylene group free from a substituent, still morepreferably a methylene group (—CH₂—), an ethylene group (—C₂H₄—), anisopropylene group (—CH(CH₃)CH₂—), or a propylene group (—C₃H₆—).

Any two of R^(1b), R^(2b), R^(3b), and R^(4b) may bind to each other toform a ring.

In the formula (b), n is an integer of 1 or greater; n is preferably aninteger of 1 to 40, more preferably an integer of 1 to 30, still morepreferably an integer of 5 to 25.

In the formula (b), p and q are each individually an integer of 0 orgreater; p is preferably an integer of 0 to 10, more preferably 0 or 1,while q is preferably an integer of 0 to 10, more preferably an integerof 0 to 5.

The sum of n, p, and q is preferably an integer of 6 or greater. The sumof n, p, and q is more preferably an integer of 8 or greater. The sum ofn, p, and q is also preferably an integer of 60 or smaller, morepreferably an integer of 50 or smaller, still more preferably an integerof 40 or smaller.

In the formula (b), A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H,a metal atom, NR^(5b)4, imidazolium optionally containing a substituent,pyridinium optionally containing a substituent, or phosphoniumoptionally containing a substituent, wherein R^(5b)s are each H or anorganic group, and are the same as or different from each other. R^(5b)is preferably H or a C1-C10 organic group, more preferably H or a C1-C4organic group. Examples of the metal atom include alkali metals(Group 1) and alkaline earth metals (Group 2), and preferred is Na, K,or Li. X^(b) may be a metal atom or NR^(5b) ₄ (wherein R^(5b) is definedas described above).

X^(b) is preferably H, an alkali metal (Group 1), an alkaline earthmetal (Group 2), or NR^(5b) ₄, more preferably H, Na, K, Li, or NH₄because they are easily dissolved in water, still more preferably Na, K,or NH₄ because they are more easily dissolved in water, particularlypreferably Na or NH₄, most preferably NH₄ because it can be easilyremoved. When X^(b) is NH₄, the surfactant can have excellent solubilityin an aqueous medium and the metal component is less likely to remain inthe fluoropolymer or the final product.

In the formula (b), L is a single bond, —CO₂—B—*, —OCO—B—*,—CONR^(6b)—B—*, —NR^(6b)CO—B—*, or —CO— other than the carbonyl groupsin —CO₂—B—, —OCO—B—, —CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is asingle bond or a C1-C10 alkylene group optionally containing asubstituent, R^(6b) is H or a C1-C4 alkyl group optionally containing asubstituent. The alkylene group more preferably contains 1 to 5 carbonatoms. R^(6b) is more preferably H or a methyl group. The symbol *indicates the bond to A^(b) in the formula.

L is preferably a single bond.

The surfactant preferably has a ¹H-NMR spectrum in which all peakintensities observed in a chemical shift range of 2.0 to 5.0 ppm give anintegral of 10 or higher.

The surfactant preferably has a ¹H-NMR spectrum in which all peakintensities observed in a chemical shift range of 2.0 to 5.0 ppm give anintegral within the above range. In this case, the surfactant preferablyhas a ketone structure in the molecule.

The integral of the surfactant is more preferably 15 or greater, whilepreferably 95 or smaller, more preferably 80 or smaller, still morepreferably 70 or smaller.

The integral is determined using a heavy water solvent at roomtemperature. The heavy water content is adjusted to 4.79 ppm.

Examples of the surfactant (a) include the following surfactants. Ineach formula, A^(a) is defined as described above.

The surfactant (a) is a novel compound, and can be produced by any ofthe following production methods, for example.

The surfactant (a) may suitably be produced by a production methodincluding:

a step (11a) of reacting a compound (10a) represented by the followingformula:

(wherein R^(3a) is defined as described above; and E^(a) is a leavinggroup), lithium, and a chlorosilane compound represented by the formula:R^(201a) ₃Si—Cl (wherein R^(201a)s are each individually an alkyl groupor an aryl group) to provide a compound (11a) represented by thefollowing formula:

(wherein R^(3a), R^(201a), and E^(a) are defined as described above);

a step (12a) of reacting the compound (11a) and an olefin represented bythe following formula:

(wherein R^(1a) is defined as described above; and R^(21a) is a singlebond or a divalent linking group) to provide a compound (12a)represented by the following formula:

(wherein R^(1a), R^(21a), R^(3a), and E^(a) are defined as describedabove);

a step (13a) of eliminating the leaving group in the compound (12a) toprovide a compound (13a) represented by the following formula:

(wherein R^(1a), R^(21a), and R^(3a) are defined as described above);and a step (14a) of oxidizing the compound (13a) to provide a compound(14a) represented by the following formula:

(wherein R^(1a), R^(21a), and R^(3a) are defined as described above.

When R^(1a) contains a furan ring, the furan ring may be cleaved with anacid and converted into a dicarbonyl derivative, for example. Examplesof the acid include acetic acid, hydrochloric acid, andp-toluenesulfonic acid. Acetic acid is preferred.

In the step (11a), the compound (11a) is preferably obtained by reactinglithium and the chlorosilane compound in advance to provide asiloxylithium compound, and then reacting this siloxylithium compoundand the compound (10a).

E^(a) represents a leaving group. Examples of the leaving group includea tert-butyldimethylsilyl (TBS) group, a triethylsilyl (TES) group, atriisopropylsilyl (TIPS) group, a tert-butyldiphenylsilyl (TBDPS) group,and a benzyl (Bn) group.

R^(21a) is preferably a single bond or a linear or branched alkylenegroup containing one or more carbon atoms.

Examples of the chlorosilane compound include the following.

Any of the reactions in the step (11a) may be performed in a solvent.The solvent is preferably an organic solvent, more preferably an aproticpolar solvent, still more preferably an ether. Examples of the etherinclude ethyl methyl ether, diethyl ether, monoglyme (ethylene glycoldimethyl ether), diglyme (diethylene glycol dimethyl ether), triglyme(triethylene glycol dimethyl ether), tetrahydrofuran, tetraglyme(tetraethylene glycol dimethyl ether), and crown ethers (e.g.,15-crown-5, 18-crown-6). Tetrahydrofuran and diethyl ether arepreferred.

The temperature of the reaction between lithium and the chlorosilanecompound in the step (11a) is preferably −78° C. to 100° C., morepreferably 10° C. to 40° C. The temperature of the reaction between thesiloxylithium compound and the compound (10a) in the step (11a) ispreferably −100° C. to 0° C., more preferably −80° C. to −50° C.

The pressure of the reaction between lithium and the chlorosilanecompound in the step (11a) is preferably 0.1 to 5 MPa, more preferably0.1 to 1 MPa.

The pressure of the reaction between the siloxylithium compound and thecompound (10a) in the step (11a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The duration of the reaction between lithium and the chlorosilanecompound in the step (11a) is preferably 0.1 to 72 hours, morepreferably 6 to 10 hours.

The duration of the reaction between the siloxylithium compound and thecompound (10a) in the step (11a) is preferably 0.1 to 72 hours, morepreferably 1 to 2 hours.

For the reaction ratio between the compound (11a) and the olefin in thestep (12a), the amount of the olefin is preferably 1 to 2 mol, morepreferably 1 to 1.1 mol, relative to 1 mol of the compound (11a), so asto improve the yield and to reduce the waste.

The reaction in the step (12a) may be performed in a solvent in thepresence of a thiazolium salt or a base.

Examples of the thiazolium salt include3-ethyl-5-(2-hydroxyethyl)-4-methylthiazolium bromide and3-benzyl-5-(2-hydroxyethyl)-4-methylthiazolium chloride.

Examples of the base include 1,8-diazabicyclo[5.4.0]-7-undecene andtriethylamine.

The solvent is preferably an organic solvent, more preferably an aproticpolar solvent, still more preferably an alcohol or an ether.

Examples of the alcohol include methanol, ethanol, 1-propanol, andisopropanol.

Examples of the ether include ethyl methyl ether, diethyl ether,monoglyme(ethylene glycol dimethyl ether), diglyme(diethylene glycoldimethyl ether), triglyme(triethylene glycol dimethyl ether),tetrahydrofuran, tetraglyme(tetraethylene glycol dimethyl ether), andcrown ethers (e.g., 15-crown-5, 18-crown-6). Tetrahydrofuran and diethylether are preferred.

The reaction temperature in the step (12a) is preferably 40° C. to 60°C., more preferably 50° C. to 55° C.

The reaction pressure in the step (12a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (12a) is preferably 0.1 to 72 hours,more preferably 6 to 10 hours.

The elimination reaction for the leaving group in the step (13a) may beperformed using a fluoride ion or an acid. Examples of methods ofeliminating the leaving group include a method using hydrofluoric acid;a method using an amine complex of hydrogen fluoride such aspyridine-nHF or triethylamine-nHF; a method using an inorganic salt suchas cesium fluoride, potassium fluoride, lithium tetrafluoroborate(LiBF₄), or ammonium fluoride; and a method using an organic salt suchas tetrabutylammonium fluoride (TBAF).

The elimination reaction for the leaving group in the step (13a) may beperformed in a polar solvent. The solvent is preferably an organicsolvent, more preferably an aprotic polar solvent, still more preferablyan ether.

Examples of the ether include ethyl methyl ether, diethyl ether,monoglyme(ethylene glycol dimethyl ether), diglyme(diethylene glycoldimethyl ether), triglyme(triethylene glycol dimethyl ether),tetrahydrofuran, tetraglyme(tetraethylene glycol dimethyl ether), andcrown ethers (e.g., 15-crown-5, 18-crown-6). Tetrahydrofuran and diethylether are preferred.

The reaction temperature in the step (13a) is preferably 0° C. to 40°C., more preferably 0° C. to 20° C.

The reaction pressure in the step (13a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (13a) is preferably 0.1 to 72 hours,more preferably 3 to 8 hours.

The oxidation in the step (14a) may be performed in a solvent in thepresence of sodium chlorite.

Examples of the solvent to be used include alcohols such as methanol,ethanol, 1-propanol, isopropanol, 1-butanol, and tert-butyl alcohol, andwater. A solution of disodium hydrogen phosphate may be used as abuffer.

The compound (14a) may be brought into contact with an alkali so that—COOH may be converted into a salt form. Examples of the alkali includesodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonia.An aqueous solution of ammonia is preferably used.

The resulting compounds may be subjected to any of evaporation of asolvent or operations such as distillation and purification after therespective steps, whereby the purity of each compound may be increased.

The surfactant (a) may also suitably be produced by a production methodincluding: a step (21a) of reacting a ketone represented by thefollowing formula:

(wherein R^(3a) is defined as described above; R^(22a) is a monovalentorganic group; and E^(a) is a leaving group) and a carboxylaterepresented by the following formula:

(wherein R^(1a) is defined as described above; and R^(23a) is amonovalent organic group) to provide a compound (21a) represented by thefollowing formula:

(wherein R^(1a), R^(3a), and E^(a) are defined as described above; andR^(24a) is a single bond or a divalent linking group);

-   -   a step (22a) of eliminating the leaving group in the compound        (21a) to provide a compound (22a) represented by the following        formula:

(wherein R^(1a), R^(24a), and R^(3a) are defined as described above);and

a step (23a) of oxidizing the compound (22a) to provide a compound (23a)represented by the following formula:

(wherein R^(1a), R^(24a), and R^(3a) are defined as described above.

When R^(1a) contains a furan ring, the furan ring may be cleaved with anacid and converted into a dicarbonyl derivative, for example. Examplesof the acid include acetic acid, hydrochloric acid, andp-toluenesulfonic acid. Acetic acid is preferred.

E^(a) represents a leaving group. Examples of the leaving group includea tert-butyldimethylsilyl (TBS) group, a triethylsilyl (TES) group, atriisopropylsilyl (TIPS) group, a tert-butyldiphenylsilyl (TBDPS) group,and a benzyl (Bn) group.

R^(22a) is preferably a linear or branched alkyl group containing one ormore carbon atoms, more preferably a methyl group.

R^(23a) is preferably a linear or branched alkyl group containing one ormore carbon atoms, more preferably a methyl group.

R^(24a) is preferably a linear or branched alkylene group containing oneor more carbon atoms, more preferably a methylene group (—CH₂—).

The reaction in the step (21a) may be performed in a solvent in thepresence of a base.

Examples of the base include sodium amide, sodium hydride, sodiummethoxide, and sodium ethoxide.

The solvent is preferably an organic solvent, more preferably an aproticpolar solvent, still more preferably an alcohol or an ether.

Examples of the alcohol include methanol, ethanol, 1-propanol, andisopropanol.

Examples of the ether include ethyl methyl ether, diethyl ether,monoglyme(ethylene glycol dimethyl ether), diglyme(diethylene glycoldimethyl ether), triglyme(triethylene glycol dimethyl ether),tetrahydrofuran, tetraglyme(tetraethylene glycol dimethyl ether), andcrown ethers (e.g., 15-crown-5, 18-crown-6). Tetrahydrofuran and diethylether are preferred.

The reaction temperature in the step (21a) is preferably 0° C. to 40°C., more preferably 0° C. to 20° C.

The reaction pressure in the step (21a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (21a) is preferably 0.1 to 72 hours,more preferably 3 to 8 hours.

The elimination reaction for the leaving group in the step (22a) may beperformed using a fluoride ion or an acid. Examples of methods ofeliminating the leaving group include a method of using hydrofluoricacid; a method of using an amine complex of hydrogen fluoride such aspyridine-nHF or triethylamine-nHF; a method of using an inorganic saltsuch as cesium fluoride, potassium fluoride, lithium tetrafluoroborate(LiBF₄), or ammonium fluoride; and a method of using an organic saltsuch as tetrabutylammonium fluoride (TBAF).

The elimination reaction for the leaving group in the step (22a) may beperformed in a solvent. The solvent is preferably an organic solvent,more preferably an aprotic polar solvent, still more preferably anether.

Examples of the ether include ethyl methyl ether, diethyl ether,monoglyme(ethylene glycol dimethyl ether), diglyme(diethylene glycoldimethyl ether), triglyme(triethylene glycol dimethyl ether),tetrahydrofuran, tetraglyme(tetraethylene glycol dimethyl ether), andcrown ethers (e.g., 15-crown-5, 18-crown-6). Tetrahydrofuran and diethylether are preferred.

The reaction temperature in the step (22a) is preferably 0° C. to 40°C., more preferably 0° C. to 20° C.

The reaction pressure in the step (22a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (22a) is preferably 0.1 to 72 hours,more preferably 3 to 8 hours.

The oxidation in the step (23a) may be performed in a solvent in thepresence of sodium chlorite.

Examples of the solvent to be used include alcohols and water. Asolution of disodium hydrogen phosphate may be used as a buffer.

The compound (23a) may be brought into contact with an alkali so that—COOH may be converted into a salt form. Examples of the alkali includesodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonia.An aqueous solution of ammonia is preferably used.

The resulting compounds may be subjected to any of evaporation of asolvent or operations such as distillation and purification after therespective steps, whereby the purity of each compound may be increased.

The surfactant (a) may also suitably be produced by a method including:

a step (31a) of reacting an alkyl halide represented by the followingformula:

Y^(a)-R^(3a)—CH₂—OE^(a)

(wherein R^(3a) is defined as described above; Y^(a) is a halogen atom;and E^(a) is a leaving group) and lithium acetylide represented by thefollowing formula:

(wherein R^(1a) is defined as described above) to provide a compound(31a) represented by the following formula:

(wherein R^(1a), R^(3a), and E^(a) are defined as described above);

a step (32a) of oxidizing the compound (31a) to provide a compound (32a)represented by the following formula:

(wherein R^(1a), R^(3a), and E^(a) are defined as described above);

a step (33a) of eliminating the leaving group in the compound (32a) toprovide a compound (33a) represented by the following formula:

(wherein R^(1a) and R^(3a) are defined as described above); and

a step (34a) of oxidizing the compound (33a) to provide a compound (34a)represented by the following formula:

(wherein R^(1a) and R^(3a) are defined as described above).

When R^(1a) contains a furan ring, the furan ring may be cleaved with anacid and converted into a dicarbonyl derivative, for example. Examplesof the acid include acetic acid, hydrochloric acid, andp-toluenesulfonic acid. Acetic acid is preferred.

E^(a) represents a leaving group. Examples of the leaving group includea tert-butyldimethylsilyl (TBS) group, a triethylsilyl (TES) group, atriisopropylsilyl (TIPS) group, a tert-butyldiphenylsilyl (TBDPS) group,and a benzyl (Bn) group.

For the reaction ratio between the alkyl halide and the lithiumacetylide in the step (31a), the amount of the lithium acetylide ispreferably 1 to 2 mol, more preferably 1 to 1.2 mol, relative to 1 molof the alkyl halide, so as to improve the yield and to reduce the waste.

The reaction in the step (31a) may be performed in a solvent. Thesolvent is preferably hexane.

The reaction temperature in the step (31a) is preferably −100° C. to−40° C., more preferably −80° C. to −50° C.

The reaction pressure in the step (31a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (31a) is preferably 0.1 to 72 hours,more preferably 6 to 10 hours.

The oxidation in the step (32a) may be performed in a nitrile solventusing a complex generated by treating [(Cn*)Ru^(III)(CF₃CO₂)₃].H₂O(wherein Cn* is 1,4,7-trimethyl-1,4,7-triazabicyclononane) with(NH₄)₂Ce(NO₃)₆ and trifluoroacetic acid and then adding sodiumperchlorate thereto.

After the oxidation is completed, the product may be neutralized with analkali, and then an organic solvent such as an ether may be used toextract the compound (32a).

The reaction temperature in the step (32a) is preferably 30° C. to 100°C., more preferably 40° C. to 90° C.

The reaction pressure in the step (32a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (32a) is preferably 0.1 to 72 hours,more preferably 3 to 8 hours.

The elimination reaction for the leaving group in the step (33a) may beperformed using a fluoride ion or an acid. Examples of methods ofeliminating the leaving group include a method of using hydrofluoricacid; a method of using an amine complex of hydrogen fluoride such aspyridine-nHF or triethylamine-nHF; a method of using an inorganic saltsuch as cesium fluoride, potassium fluoride, lithium tetrafluoroborate(LiBF₄), or ammonium fluoride; and a method of using an organic saltsuch as tetrabutylammonium fluoride (TBAF).

The elimination reaction for the leaving group in the step (33a) may beperformed in a solvent. The solvent is preferably an organic solvent,more preferably an aprotic polar solvent, still more preferably anether.

Examples of the ether include ethyl methyl ether, diethyl ether,monoglyme(ethylene glycol dimethyl ether), diglyme(diethylene glycoldimethyl ether), triglyme(triethylene glycol dimethyl ether),tetrahydrofuran, tetraglyme(tetraethylene glycol dimethyl ether), andcrown ethers (e.g., 15-crown-5, 18-crown-6). Tetrahydrofuran and diethylether are preferred.

The reaction temperature in the step (33a) is preferably 0° C. to 40°C., more preferably 0° C. to 20° C.

The reaction pressure in the step (33a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (33a) is preferably 0.1 to 72 hours,more preferably 3 to 8 hours.

The oxidation in the step (34a) may be performed in a solvent in thepresence of sodium chlorite.

Examples of the solvent to be used include alcohols and water. Asolution of disodium hydrogen phosphate may be used as a buffer.

The compound (34a) may be brought into contact with an alkali so that—COOH may be converted into a salt form. Examples of the alkali includesodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonia.An aqueous solution of ammonia is preferably used.

The resulting compounds may be subjected to any of evaporation of asolvent or operations such as distillation and purification after therespective steps, whereby the purity of each compound may be increased.

The surfactant (a) may also suitably be produced by a method including:

a step (51a) of reacting divinyl ketone represented by the followingformula:

and 2-methylfuran represented by the following formula:

to provide a compound (51a) represented by the following formula:

a step (52a) of reacting the compound (51a) and furan represented by thefollowing formula:

to provide a compound (52a) represented by the following formula:

a step (53a) of heating the compound (52a) in the presence of an acid toprovide a compound (53a) represented by the following formula:

and

a step (54a) of oxidizing the compound (53a) to provide a compound (54a)represented by the following formula:

For the reaction ratio between the divinyl ketone and the 2-methylfuranin the step (51a), the amount of the 2-methylfuran is preferably 0.5 to1 mol, more preferably 0.6 to 0.9 mol, relative to 1 mol of the divinylketone, so as to improve the yield and to reduce the waste.

The reaction in the step (51a) is preferably performed in the presenceof an acid. Examples of the acid include acetic acid, hydrochloric acid,and p-toluenesulfonic acid. Acetic acid is preferred.

The amount of the acid used in the step (51a) is preferably 0.1 to 2mol, more preferably 0.1 to 1 mol, relative to 1 mol of the divinylketone, so as to improve the yield and to reduce the waste.

The reaction in the step (51a) may be performed in a polar solvent. Thesolvent is preferably water or acetonitrile.

The reaction temperature in the step (51a) is preferably 20° C. to 100°C., more preferably 40° C. to 100° C.

The reaction pressure in the step (51a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (51a) is preferably 0.1 to 72 hours,more preferably 4 to 8 hours.

For the reaction ratio between the compound (51a) and the furan in thestep (52a), the amount of the furan is preferably 1 to 2 mol, morepreferably 1 to 1.1 mol, relative to 1 mol of the compound (51a), so asto improve the yield and to reduce the waste.

The reaction in the step (52a) is preferably performed in the presenceof an acid. Examples of the acid include acetic acid, hydrochloric acid,and p-toluenesulfonic acid. Acetic acid is preferred.

The amount of the acid used in the step (52a) is preferably 0.1 to 2mol, more preferably 0.1 to 1 mol, relative to 1 mol of the compound(51a), so as to improve the yield and to reduce the waste.

The reaction in the step (52a) may be performed in a polar solvent. Thesolvent is preferably water.

The reaction temperature in the step (52a) is preferably 20° C. to 100°C., more preferably 40° C. to 100° C.

The reaction pressure in the step (52a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (52a) is preferably 0.1 to 72 hours,more preferably 4 to 8 hours.

In the step (53a), the compound (52a) is heated in the presence of anacid so that the furan ring is cleaved.

The acid is preferably a hydrochloric acid or sulfuric acid.

The reaction in the step (53a) may be performed in a polar solvent. Thesolvent is preferably water.

The reaction temperature in the step (53a) is preferably 50° C. to 100°C., more preferably 70° C. to 100° C.

The reaction pressure in the step (53a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (53a) is preferably 0.1 to 72 hours,more preferably 1 to 12 hours.

The oxidation in the step (54a) may be performed in a solvent in thepresence of sodium chlorite.

Examples of the solvent to be used include tert-butyl alcohol and water.A solution of disodium hydrogen phosphate may be used as a buffer.

The compound (54a) may be brought into contact with an alkali so that—COOH may be converted into a salt form. Examples of the alkali includesodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonia.An aqueous solution of ammonia is preferably used.

The resulting compounds may be subjected to any of evaporation of asolvent or operations such as distillation and purification after therespective steps, whereby the purity of each compound may be increased.

The surfactant (a) may also suitably be produced by a production methodincluding: a step (61a) of reacting an alkene represented by thefollowing formula:

(wherein R^(1a) is defined as described above; and R^(21a) is a singlebond or a divalent linking group) and an alkyne represented by thefollowing formula:

(wherein Y^(61a) is an alkyl ester group) to provide a compound (61a)represented by the following formula:

(wherein R^(1a), R^(21a), and Y^(61a) are defined as described above);and a step (62a) of allowing an alkali to act on the compound (61a) andthen allowing an acid to act thereon to provide a compound (62a)represented by the following formula:

(wherein R^(1a) and R^(21a) are defined as described above).

When R^(1a) contains a furan ring, the furan ring may be cleaved with anacid and converted into a dicarbonyl derivative, for example. Examplesof the acid include acetic acid, hydrochloric acid, andp-toluenesulfonic acid. Acetic acid is preferred.

R^(21a) is preferably a single bond or a linear or branched alkylenegroup containing one or more carbon atoms.

For the reaction ratio between the alkene and the alkyne in the step(61a), the amount of the alkene is preferably 0.5 to 2 mol, morepreferably 0.6 to 1.2 mol, relative to 1 mol of the alkyne, so as toimprove the yield and to reduce the waste.

The reaction in the step (61a) is preferably performed in the presenceof a metal catalyst. An example of the metal is ruthenium.

The amount of the metal catalyst used in the step (61a) is preferably0.01 to 0.4 mol, more preferably 0.05 to 0.1 mol, relative to 1 mol ofthe alkene, so as to improve the yield and to reduce the waste.

The reaction in the step (61a) may be performed in a polar solvent. Thesolvent is preferably water, acetonitrile, dimethylacetamide, ordimethylformamide.

The reaction temperature in the step (61a) is preferably 20° C. to 160°C., more preferably 40° C. to 140° C.

The reaction pressure in the step (61a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (61a) is preferably 0.1 to 72 hours,more preferably 4 to 8 hours.

For the reaction ratio between the compound (61a) and the alkali in thestep (62a), the amount of the alkali is preferably 0.6 to 2 mol, morepreferably 0.8 to 1.1 mol, relative to 1 mol of the compound (61a), soas to improve the yield and to reduce the waste.

The amount of the acid used in the step (62a) is preferably 1.0 to 20.0mol, more preferably 1.0 to 10.0 mol, relative to 1 mol of the compound(61a), so as to improve the yield and to reduce the waste.

The reaction in the step (62a) may be performed in a polar solvent. Thesolvent is preferably water.

The reaction temperature in the step (62a) is preferably 0° C. to 100°C., more preferably 20° C. to 100° C.

The reaction pressure in the step (62a) is preferably 0.1 to 5 MPa, morepreferably 0.1 to 1 MPa.

The reaction duration in the step (62a) is preferably 0.1 to 72 hours,more preferably 4 to 8 hours.

The compound (62a) may be brought into contact with an alkali so that—COOH may be converted into a salt form. Examples of the alkali includesodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonia.An aqueous solution of ammonia is preferably used.

The resulting compounds may be subjected to any of evaporation of asolvent or operations such as distillation and purification after therespective steps, whereby the purity of each compound may be increased.

Examples of the surfactant (b) include

-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂COOK,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C H₂COONa,-   (CH₃)₃CC(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂COONa,-   (CH₃)₂CHC(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂COONa,-   (CH₂)₅CHC(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂COONa,-   CH₃CH₂C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂COONa,-   CH₃CH₂CH₂C(O)CH₂CH₂CH₂CH₂CH₂CH₂COONa,-   CH₃CH₂CH₂CH₂C(O)CH₂CH₂CH₂CH₂CH₂COONa,-   CH₃CH₂CH₂CH₂CH₂C(O)CH₂CH₂CH₂CH₂COONa,-   CH₃CH₂CH₂CH₂CH₂CH₂C(O)CH₂CH₂CH₂COONa,-   CH₃CH₂CH₂CH₂CH₂CH₂CH₂C(O)CH₂CH₂COONa,-   CH₃CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂OCH₂CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)NHCH₂COOK,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂NHC(O)CH₂COOK,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)OCH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂OC(O)CH₂COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)COONa,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)COOH,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)COOLi,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)COONH₄,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)COONa,    CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(CH₃)₂COOK,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C H₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   (CH₃)₃CC(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   (CH₃)₂CHC(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   (CH₂)₅CHC(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂SO₃Na,-   CH₃C(O)CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂OCH₂CH₂CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)NHCH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂NHC(O)CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(O)OCH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂OC(O)CH₂SO₃Na,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃H,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃K,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃Li,-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂SO₃NH₄, and-   CH₃C(O)CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂C(CH₃)₂SO₃Na.

The surfactant (b) is a novel compound, and can be produced by any ofthe following production methods, for example.

The surfactant (b) may suitably be produced by a production methodincluding: a step (11b) of reacting a compound (10b) represented by thefollowing formula:

(wherein R^(1b), R^(2b), and n are defined as described above) and asultone represented by the following formula:

(wherein R^(3b) is defined as described above; L is a single bond,—CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*, or —CO— other thanthe carbonyl groups in —CO₂—B—, —OCO—B—, —CONR^(6b)—B—, and—NR^(6b)CO—B—, where B is a single bond or a C1-C10 alkylene groupoptionally containing a substituent, R^(6b) is H or a C1-C4 alkyl groupoptionally containing a substituent, and * indicates the bond to—S(═O)₂— in the formula) to provide a compound (11 b) represented by thefollowing formula:

(wherein R^(1b) to R^(3b), n, and X^(b) are defined as described above;L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to —OSO₃X^(b) in the formula).

The reaction in the step (11b) may be performed in the presence of abase.

Examples of the base include sodium hydride, sodium hydroxide, potassiumhydroxide, and triethylamine. The base may be used in an amount of 0.5to 20 mol relative to 1 mol of the compound (10b).

The reaction in the step (11b) may be performed in a solvent.

The solvent is preferably an organic solvent, more preferably an aproticpolar solvent. Examples of the organic solvent include ethers, aromaticcompounds, nitriles, and halogenated hydrocarbons.

Examples of the ethers include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the aromatic hydrocarbons include benzene, toluene, andxylene. Benzene is preferred.

Examples of the nitriles include acetonitrile, propionitrile,butyronitrile, isobutyronitrile, and benzonitrile. Acetonitrile ispreferred.

Examples of the halogenated hydrocarbons include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

The reaction temperature in the step (11b) is preferably −78° C. to 150°C., more preferably −20° C. to 100° C.

The reaction pressure in the step (11b) is preferably 0 to 10 MPa, morepreferably 0 to 1.0 MPa.

The reaction duration in the step (11 b) is preferably 0.1 to 72 hours,more preferably 0.1 to 48 hours.

The surfactant (b) may also suitably be produced by a production methodincluding: a step (21b) of oxidizing a compound (20b) represented by thefollowing formula:

(wherein R^(1b) to R^(4b), n, p, and q are defined as described above; Lis a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*, or—CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—, —CONR^(6b)—B—,and —NR^(6b)CO—B—, where B is a single bond or a C1-C10 alkylene groupoptionally containing a substituent, R^(6b) is H or a C1-C4 alkyl groupoptionally containing a substituent, and * indicates the bond to —CH₂—OHin the formula) to provide a compound (21b) represented by the followingformula:

(wherein R^(1b) to R^(4b), n, p, q, and X^(b) are defined as describedabove; L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*,—NR^(6b)CO—B—*, or —CO— other than the carbonyl groups in —CO₂—B—,—OCO—B—, —CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or aC1-C10 alkylene group optionally containing a substituent, R^(6b) is Hor a C1-C4 alkyl group optionally containing a substituent, and *indicates the bond to —CH₂—COOX^(b) in the formula).

The oxidation in the step (21b) may be performed by allowing anitrosating agent to act on the compound (20b).

Examples of the nitrosating agent include sodium nitrite,nitrosylsulfuric acid, and isoamyl nitrite.

The nitrosating agent may be used in an amount of 0.5 to 10 mol relativeto 1 mol of the compound (20b).

The oxidation in the step (21b) may be performed in a solvent. Thesolvent used may be trifluoroacetic acid or acetonitrile, for example.

The oxidation temperature in the step (21b) is preferably −78° C. to200° C., more preferably −20° C. to 100° C.

The oxidation pressure in the step (21b) is preferably 0 to 10 MPa, morepreferably 0 to 1.0 MPa.

The oxidation duration in the step (21b) is preferably 0.1 to 72 hours,more preferably 0.1 to 24 hours.

The compound (10b) and the compound (20b) each may be produced by aproduction method including:

a step (101b) of hydroxylating a compound (100b) represented by thefollowing formula:

R^(11b)—CH═CH—Y^(1b)—OH

(wherein R^(11b) is H, a linear or branched alkyl group containing oneor more carbon atoms and optionally containing a substituent, or acyclic alkyl group containing three or more carbon atoms and optionallycontaining a substituent, and optionally contains a monovalent ordivalent heterocycle or optionally forms a ring when containing three ormore carbon atoms; Y^(1b) is —(CR^(2b) ₂)_(n)— or —(CR^(2b)₂)_(n)—(OR^(3b))_(p)—(CR^(4b) ₂)_(q)-L-CH₂—, where R^(2b) to R^(4b), n,L, p, and q are defined as described above; L is a single bond,—CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*, or —CO— other thanthe carbonyl groups in —CO₂—B—, —OCO—B—, —CONR^(6b)—B—, and—NR^(6b)CO—B—, where B is a single bond or a C1-C10 alkylene groupoptionally containing a substituent, R^(6b) is H or a C1-C4 alkyl groupoptionally containing a substituent, and * indicates the bond to —CH₂—in the formula) to provide a compound (101b) represented by thefollowing formula:

(wherein R^(1b) and Y^(1b) are defined as described above); and a step(102b) of oxidizing the compound (101b) to provide a compound (102b)represented by the following formula:

(wherein R^(b) and Y^(1b) are defined as described above).

The alkyl group for R^(1b) is preferably free from a carbonyl group.

In the alkyl group for R^(11b), 75% or less of the hydrogen atomsbinding to any of the carbon atoms may be replaced by halogen atoms, 50%or less thereof may be replaced by halogen atoms, or 25% or less thereofmay be replaced by halogen atoms. The alkyl group is preferably anon-halogenated alkyl group containing no halogen atoms such as fluorineatoms and chlorine atoms.

The alkyl group preferably contains no substituent.

R^(11b) is preferably H, a C1-C9 linear or branched alkyl groupoptionally containing a substituent, or a C3-C9 cyclic alkyl groupoptionally containing a substituent, more preferably H, a C1-C9 linearor branched alkyl group free from a carbonyl group, or a C3-C9 cyclicalkyl group free from a carbonyl group, still more preferably H or aC1-C9 linear or branched alkyl group free from a substituent, furthermore preferably H, a methyl group (—CH₃), or an ethyl group (—C₂H₅),particularly preferably H or a methyl group (—CH₃), most preferably H.

The hydroxylation in the step (101b) may be performed by a method (1b)in which iron(II) phthalocyanine (Fe(Pc)) and sodium borohydride areallowed to act on the compound (100b) in an oxygen atmosphere or amethod (2b) in which isopinocampheylborane (IpcBH₂) is allowed to act onthe compound (100b) and then the resulting intermediate (dialkyl borane)is oxidized.

In the method (1b), iron(II) phthalocyanine may be used in a catalyticamount, and may be used in an amount of 0.001 to 1.2 mol relative to 1mol of the compound (100b).

In the method (1b), sodium borohydride may be used in an amount of 0.5to 20 mol relative to 1 mol of the compound (100b).

The reaction in the method (1b) may be performed in a solvent. Thesolvent is preferably an organic solvent, such as an ether, ahalogenated hydrocarbon, an aromatic hydrocarbon, a nitrile, or anitrogen-containing polar organic compound.

Examples of the ether include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the halogenated hydrocarbon include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

Examples of the aromatic hydrocarbon include benzene, toluene, andxylene. Benzene and toluene are preferred.

Examples of the nitrile include acetonitrile, propionitrile,butyronitrile, isobutyronitrile, and benzonitrile. Acetonitrile ispreferred.

Examples of the nitrogen-containing polar organic compound includeN,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone,2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidoneare preferred.

The reaction temperature in the method (1b) is preferably −78° C. to200° C., more preferably 0° C. to 150° C.

The reaction pressure in the method (1b) is preferably 0 to 5.0 MPa,more preferably 0.1 to 1.0 MPa.

The reaction duration in the method (1b) is preferably 0.1 to 72 hours,more preferably 0.1 to 48 hours.

In the method (2b), isopinocampheylborane may be used in an amount of1.0 to 10.0 mol relative to 1 mol of the compound (100b).

The reaction of the compound (100b) and isopinocampheylborane may beperformed in a solvent. The solvent is preferably an organic solvent,such as an ether, a halogenated hydrocarbon, or an aromatic hydrocarbon.

Examples of the ether include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the halogenated hydrocarbon include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

Examples of the aromatic hydrocarbon include benzene, toluene, andxylene. Benzene and toluene are preferred.

The temperature of the reaction of the compound (100b) andisopinocampheylborane is preferably −78° C. to 200° C., more preferably0° C. to 150° C.

The pressure of the reaction of the compound (100b) andisopinocampheylborane is preferably 0 to 5.0 MPa, more preferably 0.1 to1.0 MPa.

The duration of the reaction of the compound (100b) andisopinocampheylborane is preferably 0.1 to 72 hours, more preferably 0.1to 48 hours.

The oxidation in the method (2b) may be performed by allowing anoxidizing agent to act on the intermediate. An example of the oxidizingagent is hydrogen peroxide. The oxidizing agent may be used in an amountof 0.7 to 10 mol relative to 1 mol of the intermediate.

The oxidation in the method (2b) may be performed in a solvent. Examplesof the solvent include water, methanol, and ethanol. Water is preferred.

The oxidation temperature in the method (2b) is preferably 0° C. to 100°C., more preferably 0° C. to 80° C.

The oxidation pressure in the method (2b) is preferably 0 to 5.0 MPa,more preferably 0.1 to 1.0 MPa.

The oxidation duration in the method (2b) is preferably 0.1 to 72 hours,more preferably 0.1 to 48 hours.

The oxidation of the compound (101b) in the step (102b) may be performedby, for example, (a) a method using the Jones reagent (CrO₃/H₂SO₄)(Jones oxidation), (b) a method using Dess-Martin periodinane (DMP)(Dess-Martin oxidation), (c) a method using pyridinium chlorochromate(PCC), (d) a method of allowing a bleaching agent (about 5% to 6%aqueous solution of NaOCl) to act in the presence of a nickel compoundsuch as NiCl₂, or (e) a method of allowing a hydrogen acceptor such asan aldehyde or a ketone to act in the presence of an aluminum catalystsuch as Al(CH₃)₃ or Al[OCH(CH₃)₂]₃ (Oppenauer oxidation).

The oxidation in the step (102b) may be performed in a solvent. Thesolvent is preferably any of water and organic solvents, such as water,ketones, ethers, halogenated hydrocarbons, aromatic hydrocarbons, andnitriles.

Examples of the ketones include acetone, methyl ethyl ketone, methylisobutyl ketone, cyclohexanone, and diacetone alcohol. Acetone ispreferred.

Examples of the ethers include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the halogenated hydrocarbons include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

Examples of the aromatic hydrocarbons include benzene, toluene, andxylene. Benzene and toluene are preferred.

Examples of the nitriles include acetonitrile, propionitrile,butyronitrile, isobutyronitrile, and benzonitrile. Acetonitrile ispreferred.

The oxidation temperature in the step (102b) is preferably −78° C. to200° C., and may appropriately be selected in accordance with the methodused.

The oxidation pressure in the step (102b) is preferably 0 to 5.0 MPa,and may appropriately be selected in accordance with the method used.

The oxidation duration in the step (102b) is preferably 0.1 to 72 hours,and may appropriately be selected in accordance with the method used.

The compound (10b) and the compound (20b) each may also be produced by aproduction method including:

a step (201b) of ozonolyzing a compound (200b) represented by thefollowing formula:

(wherein R^(1b) and Y^(1b) are defined as described above; and R¹⁰1b isan organic group) to provide a compound (201b) represented by thefollowing formula:

(wherein R^(1b) and Y^(1b) are defined as described above).

R^(101b)s are each preferably a C1-C20 alkyl group. The two R^(101b)sare the same as or different from each other.

The ozonolysis in the step (201b) may be performed by allowing ozone toact on the compound (200b), followed by post-treatment with a reducingagent.

The ozone may be generated by dielectric barrier discharge in oxygengas.

Examples of the reducing agent used in the post-treatment include zinc,dimethyl sulfide, thiourea, and phosphines. Phosphines are preferred.

The ozonolysis in the step (201b) may be performed in a solvent. Thesolvent is preferably any of water and organic solvents, such as water,alcohols, carboxylic acids, ethers, halogenated hydrocarbons, andaromatic hydrocarbons.

Examples of the alcohols include methanol, ethanol, 1-propanol, andisopropanol. Methanol and ethanol are preferred.

Examples of the carboxylic acids include acetic acid and propionic acid.Acetic acid is preferred.

Examples of the ethers include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the halogenated hydrocarbons include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

Examples of the aromatic hydrocarbons include benzene, toluene, andxylene. Benzene and toluene are preferred.

The ozonolysis temperature in the step (201b) is preferably −78° C. to200° C., more preferably 0° C. to 150° C.

The ozonolysis pressure in the step (201b) is preferably 0 to 5.0 MPa,more preferably 0.1 to 1.0 MPa.

The ozonolysis duration in the step (201b) is preferably 0.1 to 72hours, more preferably 0.1 to 48 hours.

The compound (10b) and the compound (20b) each may also be produced by aproduction method including:

a step (301b) of epoxidizing a compound (300b) represented by thefollowing formula:

R^(21b)—CH═CH—Y^(1b)—OH

(wherein Y^(1b) is defined as described above; R^(21b) is H, a linear orbranched alkyl group containing one or more carbon atoms and optionallycontaining a substituent, or a cyclic alkyl group containing three ormore carbon atoms and optionally containing a substituent, andoptionally contains a monovalent or divalent heterocycle or optionallyforms a ring when containing three or more carbon atoms) to provide acompound (301b) represented by the following formula:

(wherein R^(21b) and Y^(1b) are defined as described above);

a step (302b) of reacting the compound (301b) with a dialkylcopperlithium represented by R^(22b) ₂CuLi (wherein R^(22b) is a linear orbranched alkyl group containing one or more carbon atoms and optionallycontaining a substituent or a cyclic alkyl group containing three ormore carbon atoms and optionally containing a substituent, andoptionally contains a monovalent or divalent heterocycle or optionallyforms a ring when containing three or more carbon atoms) to provide acompound (302b) represented by the following formula:

(wherein R^(21b), R^(22b), and Y^(1b) are defined as described above);and a step (303b) of oxidizing the compound (302b) to provide a compound(303b) represented by the following formula:

(wherein R^(21b), R^(22b), and Y^(1b) are defined as described above).

The alkyl group for R^(21b) is preferably free from a carbonyl group.

In the alkyl group for R^(21b), 75% or less of the hydrogen atomsbinding to any of the carbon atoms may be replaced by halogen atoms, 50%or less thereof may be replaced by halogen atoms, or 25% or less thereofmay be replaced by halogen atoms. The alkyl group is preferably anon-halogenated alkyl group containing no halogen atoms such as fluorineatoms and chlorine atoms.

The alkyl group preferably contains no substituent.

R^(21b) is preferably H, a C1-C8 linear or branched alkyl groupoptionally containing a substituent, or a C3-C8 cyclic alkyl groupoptionally containing a substituent, more preferably H, a C1-C8 linearor branched alkyl group free from a carbonyl group, or a C3-C8 cyclicalkyl group free from a carbonyl group, still more preferably H or aC1-C8 linear or branched alkyl group free from a substituent,particularly preferably H or a methyl group (—CH₃), most preferably H.

The alkyl group for R^(22b) is preferably free from a carbonyl group.

In the alkyl group for R^(22b), 75% or less of the hydrogen atomsbinding to any of the carbon atoms may be replaced by halogen atoms, 50%or less thereof may be replaced by halogen atoms, or 25% or less thereofmay be replaced by halogen atoms. The alkyl group is preferably anon-halogenated alkyl group containing no halogen atoms such as fluorineatoms and chlorine atoms.

The alkyl group preferably contains no substituent.

R^(22b) is preferably a C1-C9 linear or branched alkyl group optionallycontaining a substituent or a C3-C9 cyclic alkyl group optionallycontaining a substituent, more preferably a C1-C9 linear or branchedalkyl group free from a carbonyl group or a C3-C9 cyclic alkyl groupfree from a carbonyl group, still more preferably a C1-C9 linear orbranched alkyl group free from a substituent, particularly preferably amethyl group (—CH₃) or an ethyl group (—C2H₅), most preferably a methylgroup (—CH₃).

Two R^(22b)s are the same as or different from each other.

R^(21b) and R^(22b) preferably contain 1 to 7 carbon atoms, morepreferably 1 or 2 carbon atoms, most preferably 1 carbon atom, in total.

The epoxidation in the step (301b) may be performed by allowing anepoxidizing agent to act on the compound (300b).

Examples of the epoxidizing agent include peroxy acids such asmeta-chloroperbenzoic acid (m-CPBA), perbenzoic acid, hydrogen peroxide,and tert-butyl hydroperoxide, dimethyl dioxolane, and methyltrifluoromethyl dioxolane. Peroxy acids are preferred, andmeta-chloroperbenzoic acid is more preferred.

The epoxidizing agent may be used in an amount of 0.5 to 10.0 molrelative to 1 mol of the compound (300b).

The epoxidation in the step (301b) may be performed in a solvent. Thesolvent is preferably an organic solvent, such as a ketone, an ether, ahalogenated hydrocarbon, an aromatic hydrocarbon, a nitrile, pyridine, anitrogen-containing polar organic compound, or dimethyl sulfoxide.Dichloromethane is preferred.

Examples of the ketone include acetone, methyl ethyl ketone, methylisobutyl ketone, cyclohexanone, and diacetone alcohol. Acetone ispreferred.

Examples of the ether include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the halogenated hydrocarbon include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

Examples of the aromatic hydrocarbon include benzene, toluene, andxylene. Benzene and toluene are preferred.

Examples of the nitrile include acetonitrile, propionitrile,butyronitrile, isobutyronitrile, and benzonitrile. Acetonitrile ispreferred.

Examples of the nitrogen-containing polar organic compounds includeN,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone,2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidoneare preferred.

The epoxidation temperature in the step (301b) is preferably −78° C. to200° C., more preferably −40° C. to 150° C.

The epoxidation pressure in the step (301b) is preferably 0 to 5.0 MPa,more preferably 0.1 to 1.0 MPa.

The epoxidation duration in the step (301b) is preferably 0.1 to 72hours, more preferably 0.1 to 48 hours.

In the step (302b), the dialkylcopper lithium may be used in an amountof 0.5 to 10.0 mol relative to 1 mol of the compound (301b).

The reaction in the step (302b) may be performed in a solvent. Thesolvent is preferably an organic solvent, such as an ether, ahalogenated hydrocarbon, or an aromatic hydrocarbon.

Examples of the ether include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the halogenated hydrocarbon include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

Examples of the aromatic hydrocarbon include benzene, toluene, andxylene. Benzene and toluene are preferred.

The reaction temperature in the step (302b) is preferably −78° C. to200° C., more preferably −40° C. to 150° C.

The reaction pressure in the step (302b) is preferably 0 to 5.0 MPa,more preferably 0.1 to 1.0 MPa.

The reaction duration in the step (302b) is preferably 0.1 to 72 hours,more preferably 0.1 to 48 hours.

The oxidation of the compound (302b) in the step (303b) may be performedby, for example, (a) a method of using the Jones reagent (CrO₃/H₂SO₄)(Jones oxidation), (b) a method of using Dess-Martin periodinane (DMP)(Dess-Martin oxidation), (c) a method of using pyridinium chlorochromate(PCC), (d) a method of allowing a bleaching agent (about 5% to 6%aqueous solution of NaOCl) to act in the presence of a nickel compoundsuch as NiCl₂, or (e) a method of allowing a hydrogen acceptor such asan aldehyde or a ketone to act in the presence of an aluminum catalystsuch as Al(CH₃)₃ or Al[OCH(CH₃)₂]₃ (Oppenauer oxidation).

The oxidation in the step (303b) may be performed in a solvent. Thesolvent is preferably any of water and organic solvents, such as water,ketones, alcohols, ethers, halogenated hydrocarbons, aromatichydrocarbons, and nitriles.

Examples of the ketones include acetone, methyl ethyl ketone, methylisobutyl ketone, cyclohexanone, and diacetone alcohol. Acetone ispreferred.

Examples of the alcohols include methanol, ethanol, 1-propanol, andisopropanol. Methanol and ethanol are preferred.

Examples of the ethers include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the halogenated hydrocarbons include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

Examples of the aromatic hydrocarbons include benzene, toluene, andxylene. Benzene and toluene are preferred.

Examples of the nitriles include acetonitrile, propionitrile,butyronitrile, isobutyronitrile, and benzonitrile. Acetonitrile ispreferred.

The oxidation temperature in the step (303b) is preferably −78° C. to200° C., and may appropriately be selected in accordance with the methodused.

The oxidation pressure in the step (303b) is preferably 0 to 5.0 MPa,and may appropriately be selected in accordance with the method used.

The oxidation duration in the step (303b) is preferably 0.1 to 72 hours,and may appropriately be selected in accordance with the method used.

The compound (10b) and the compound (20b) each may also be produced by aproduction method including:

-   -   a step (401b) of oxidizing a compound (100b) represented by the        following formula:

R^(11b)—CH═CH—Y^(1b)—OH

(wherein R^(11b) and Y^(1b) are defined as described above) to provide acompound (401b) represented by the following formula:

(wherein R^(11b) and Y^(1b) are defined as described above).

The oxidation in the step (401b) may be performed by allowing anoxidizing agent to act on the compound (100b) in the presence of waterand a palladium compound.

Examples of the oxidizing agent include monovalent or divalent coppersalts such as copper chloride, copper acetate, copper cyanide, andcopper trifluoromethanethiolate, iron salts such as iron chloride, ironacetate, iron cyanide, iron trifluoromethanethiolate, andhexacyanoferrates, benzoquinones such as 1,4-benzoquinone,2,3-dichloro-5,6-dicyano-1,4-benzoquinone, tetrachloro-1,2-benzoquinone,and tetrachloro-1,4-benzoquinone, H₂O₂, MnO₂, KMnO₄, RuO₄,m-chloroperbenzoic acid, and oxygen. Copper salts, iron salts, andbenzoquinones are preferred, and copper chloride, iron chloride, and1,4-benzoquinone are more preferred.

The oxidizing agent may be used in an amount of 0.001 to 10 mol relativeto 1 mol of the compound (100b).

The water may be used in an amount of 0.5 to 1000 mol relative to 1 molof the compound (100b).

An example of the palladium compound is palladium dichloride. Thepalladium compound may be used in a catalytic amount, and may be used inan amount of 0.0001 to 1.0 mol relative to 1 mol of the compound (100b).

The oxidation in the step (401b) may be performed in a solvent. Examplesof the solvent include water, esters, aliphatic hydrocarbons, aromatichydrocarbons, alcohols, carboxylic acids, ethers, halogenatedhydrocarbons, nitrogen-containing polar organic compounds, nitriles,dimethyl sulfoxide, and sulfolane.

Examples of the esters include ethyl acetate, butyl acetate, ethyleneglycol monomethyl ether acetate, and propylene glycol monomethyl etheracetate (PGMEA, also known as 1-methoxy-2-acetoxypropane). Ethyl acetateis preferred.

Examples of the aliphatic hydrocarbons include hexane, cyclohexane,heptane, octane, nonane, decane, undecane, dodecane, and mineralspirits. Cyclohexane and heptane are preferred.

Examples of the aromatic hydrocarbons include benzene, toluene, andxylene. Benzene and toluene are preferred.

Examples of the alcohols include methanol, ethanol, 1-propanol, andisopropanol.

Examples of the carboxylic acids include acetic acid and propionic acid.Acetic acid is preferred.

Examples of the ethers include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether. Diethyl ether and tetrahydrofuranare preferred.

Examples of the halogenated hydrocarbons include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.Dichloromethane and chloroform are preferred.

Examples of the nitrogen-containing polar organic compounds includeN,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone,2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidoneare preferred.

Examples of the nitriles include acetonitrile, propionitrile,butyronitrile, isobutyronitrile, and benzonitrile. Acetonitrile ispreferred.

The oxidation temperature in the step (401b) is preferably −78° C. to200° C., more preferably −20° C. to 150° C.

The oxidation pressure in the step (401b) is preferably 0 to 10 MPa,more preferably 0.1 to 5.0 MPa.

The oxidation duration in the step (401b) is preferably 0.1 to 72 hours,more preferably 0.1 to 48 hours.

The surfactant (b) may also be produced by a production methodincluding: a step (31b) of oxidizing a compound (30b) represented by thefollowing formula:

R^(11b)—CH═CH—(CR^(2b) ₂)_(n)—(OR^(3b))_(p)—(CR^(4b) ₂)_(q)-L-COOX^(b)

(wherein R^(2b) to R^(4b), R^(11b), n, p, q, and X^(b) are defined asdescribed above; L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*,—NR^(6b)CO—B—*, or —CO— other than the carbonyl groups in —CO₂—B—,—OCO—B—, —CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or aC1-C10 alkylene group optionally containing a substituent, R^(6b) is Hor a C1-C4 alkyl group optionally containing a substituent, the alkylenegroup more preferably contains 1 to 5 carbon atoms, R^(6b) is morepreferably H or a methyl group, and * indicates the bond to —COOX^(b) inthe formula) to provide a compound (31b) represented by the followingformula:

(wherein R^(2b) to R^(4b), L, R^(11b), n, p, q, and X^(b) are defined asdescribed above).

The oxidation in the step (31b) may be performed by allowing anoxidizing agent to act on the compound (30b) in the presence of waterand a palladium compound under the same conditions as in the oxidationin the step (401b).

In each of the above production methods, the resulting compounds may besubjected to any of evaporation of a solvent or operations such asdistillation and purification after the respective steps, whereby thepurity of each compound may be increased. When the resulting compound isa compound in which X^(b) is H, i.e., containing —SO₃H or —COOH, thecompound may be brought into contact with an alkali such as sodiumcarbonate or ammonia so that such a group is converted into a salt form.

The surfactant may be in the form of an aqueous solution containing atleast one surfactant (1) selected from the group consisting of:

a surfactant (a) represented by the following formula (a):

(wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group; R^(1a), R^(2a), and R^(3a) contain five or more carbonatoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a) s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring); and

a surfactant (b) represented by the following formula (b):

(wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C10 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom,NR^(5b) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, the alkylenegroup more preferably contains 1 to 5 carbon atoms, R^(6b) is morepreferably H or a methyl group, and * indicates the bond to A^(b) in theformula; alternatively, L is an amide bond, an ester bond, or a carbonylgroup other than the carbonyl groups in an amide bond and an esterbond), and water.

For the surfactant (1) in the aqueous solution, the upper limit of theconcentration thereof is preferably 50% by mass, more preferably 30% bymass, still more preferably 20% by mass, further more preferably 100000ppm, still further more preferably 50000 ppm, particularly preferably10000 ppm, most preferably 5000 ppm. The lower limit thereof ispreferably 1 ppm, more preferably 10 ppm, still more preferably 50 ppm.

The surfactant is preferably a surfactant for polymerization used forproduction of a fluoropolymer or an aqueous solution of a surfactant forpolymerization used for production of a fluoropolymer.

The method for producing a fluoropolymer of the invention includespolymerizing a fluoromonomer in an aqueous medium to provide afluoropolymer. The polymerization may be emulsion polymerization.

The fluoromonomer is preferably one containing at least one double bond.

The fluoromonomer preferably includes at least one selected from thegroup consisting of tetrafluoroethylene (TFE), hexafluoropropylene(HFP), chlorotrifluoroethylene (CTFE), vinyl fluoride, vinylidenefluoride (VDF), trifluoroethylene, fluoroalkyl vinyl ether, fluoroalkylethylene, trifluoropropylene, pentafluoropropylene, trifluorobutene,tetrafluoroisobutene, hexafluoroisobutene, a fluoromonomer representedby the formula (100): CH₂═CFRf¹⁰¹ (wherein Rf¹⁰¹ is a C1-C12 linear orbranched fluoroalkyl group), a fluorinated vinyl heterocycle, and amonomer giving a crosslinking site.

The fluoroalkyl vinyl ether preferably includes at least one selectedfrom the group consisting of:

a fluoromonomer represented by the formula (110):

CF₂═CF—ORf¹¹¹

wherein Rf¹¹¹ is a perfluoroorganic group;

a fluoromonomer represented by the formula (120):

CF₂═CF—OCH₂—Rf¹²¹

wherein Rf¹²¹ is a C1-C5 perfluoroalkyl group;

a fluoromonomer represented by the formula (130):

CF₂═CFOCF₂ORf¹³¹

wherein Rf¹³¹ is a C1-C6 linear or branched perfluoroalkyl group, aC5-C6 cyclic perfluoroalkyl group, or a C2-C6 linear or branchedperfluorooxyalkyl group containing 1 to 3 oxygen atoms;

a fluoromonomer represented by the formula (140):

CF₂═CFO(CF₂CF(Y¹⁴¹)O)_(m)(CF₂)_(n)F

wherein Y¹⁴¹ is a fluorine atom or a trifluoromethyl group; m is aninteger of 1 to 4; and n is an integer of 1 to 4; and

a fluoromonomer represented by the formula (150):

CF₂═CF—O—(CF₂CFY¹⁵¹—O)_(n)—(CFY¹⁵²)_(m)-A¹⁵¹

wherein Y¹⁵¹ is a fluorine atom, a chlorine atom, a —SO₂F group, or aperfluoroalkyl group, the perfluoroalkyl group optionally containingether oxygen and a —SO₂F group; n is an integer of 0 to 3; n Y¹⁵'s arethe same as or different from each other; Y¹⁵² is a fluorine atom, achlorine atom, or a —SO₂F group; m is an integer of 1 to 5; m Y¹⁵²s arethe same as or different from each other; A¹⁵¹ is —SO₂X¹⁵¹, —COZ¹⁵¹, or—POZ¹⁵²Z¹⁵³; X¹⁵¹ is F, Cl, Br, I, —OR¹⁵¹, or —NR¹⁵²R¹⁵³; Z¹⁵¹, Z¹⁵²,and Z¹⁵³ are the same as or different from each other, and are each—NR¹⁵⁴R¹⁵⁵ or —OR¹⁵⁶; R¹⁵¹, R¹⁵², R¹⁵³, R¹⁵⁴, R¹⁵⁵, and R¹⁵⁶ are thesame as or different from each other, and are each H, ammonium, analkali metal, or an alkyl group, aryl group, or sulfonyl-containinggroup optionally containing a fluorine atom.

The “perfluoroorganic group” as used herein means an organic group inwhich all hydrogen atoms binding to any of the carbon atoms are replacedby fluorine atoms. The perfluoroorganic group optionally contains etheroxygen.

An example of the fluoromonomer represented by the formula (110) is afluoromonomer in which Rf¹¹¹ is a C1-C10 perfluoroalkyl group. Theperfluoroalkyl group preferably contains 1 to 5 carbon atoms.

Examples of the perfluoroorganic group in the formula (110) include aperfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group,a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexylgroup.

The examples of the fluoromonomer represented by the formula (110) alsoinclude those represented by the formula (110) in which Rf¹¹ is a C4-C9perfluoro(alkoxyalkyl) group; those in which Rf¹¹ is a group representedby the following formula:

wherein m is 0 or an integer of 1 to 4; and those in which Rf¹¹¹ is agroup represented by the following formula:

wherein n is an integer of 1 to 4.

The fluoroalkyl vinyl ether preferably include at least one selectedfrom the group consisting of fluoromonomers represented by any of theformulae (110), (130), and (140).

The fluoromonomer represented by the formula (110) preferably includesat least one selected from the group consisting of perfluoro(methylvinyl ether), perfluoro(ethyl vinyl ether), and perfluoro(propyl vinylether), more preferably at least one selected from the group consistingof perfluoro(methyl vinyl ether) and perfluoro(propyl vinyl ether).

The fluoromonomer represented by the formula (130) preferably includesat least one selected from the group consisting of CF₂═CFOCF₂OCF₃,CF₂═CFOCF₂OCF₂CF₃, and CF₂═CFOCF₂OCF₂CF₂OCF₃.

The fluoromonomer represented by the formula (140) preferably includesat least one selected from the group consisting ofCF₂═CFOCF₂CF(CF₃)O(CF₂)₃F, CF₂═CFO(CF₂CF(CF₃)O)₂(CF₂)₃F, andCF₂═CFO(CF₂CF(CF₃)O)₂(CF₂)₂F.

The fluoromonomer represented by the formula (150) preferably includesat least one selected from the group consisting of CF₂═CFOCF₂CF₂SO₂F,CF₂═CFOCF₂CF(CF₃)OCF₂CF₂SO₂F, CF₂═CFOCF₂CF(CF₂CF₂SO₂F)OCF₂CF₂SO₂F, andCF₂═CFOCF₂CF(SO₂F)₂.

The fluoromonomer represented by the formula (100) is preferably afluoromonomer in which Rf¹⁰¹ is a linear fluoroalkyl group, morepreferably a fluoromonomer in which Rf¹⁰¹ is a linear perfluoroalkylgroup. Rf¹⁰¹ preferably contains 1 to 6 carbon atoms. Examples of thefluoromonomer represented by the formula (100) include CH₂═CFCF₃,CH₂═CFCF₂CF₃, CH₂═CFCF₂CF₂CF₃, CH₂═CFCF₂CF₂CF₂H, and CH₂═CFCF₂CF₂CF₂CF₃.Preferred among these is 2,3,3,3-tetrafluoropropylene represented byCH₂═CFCF₃.

The fluoroalkyl ethylene is preferably a fluoroalkyl ethylenerepresented by the following formula (170):

CH₂═CH—(CF₂)_(n)—X¹⁷¹

(wherein X¹⁷¹ is H or F; and n is an integer of 3 to 10), morepreferably includes at least one selected from the group consisting ofCH₂═CH—C₄F₉ and CH₂═CH—C₆F₁₃.

The monomer giving a crosslinking site preferably includes at least oneselected from the group consisting of:

a fluoromonomer represented by the following formula (180):

CX¹⁸¹ ₂═CX¹⁸²—R_(f) ⁸¹CHR¹⁸¹X¹⁸³

wherein X¹⁸¹ and X¹⁸² are each individually a hydrogen atom, a fluorineatom, or CH₃; R⁸¹ is a fluoroalkylene group, a perfluoroalkylene group,a fluoro(poly)oxyalkylene group, or a perfluoro(poly)oxyalkylene group;R¹⁸¹ is a hydrogen atom or CH₃; X¹⁸³ is an iodine atom or a bromineatom;

a fluoromonomer represented by the following formula (190):

CX¹⁹¹ ₂═CX¹⁹²—R_(f) ¹⁹¹X¹⁹³

wherein X¹⁹¹ and X¹⁹² are each individually a hydrogen atom, a fluorineatom, or CH₃; R_(f) ¹⁹¹ is a fluoroalkylene group, a perfluoroalkylenegroup, a fluoropolyoxyalkylene group, or a perfluoropolyoxyalkylenegroup; X¹⁹³ is an iodine atom or a bromine atom; a fluoromonomerrepresented by the following formula (200):

CF₂═CFO(CF₂CF(CF₃)O)_(m)(CF₂)_(n)—X²⁰¹

wherein m is an integer of 0 to 5; n is an integer of 1 to 3; X²⁰¹ is acyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom,a bromine atom, or —CH₂I;

a fluoromonomer represented by the following formula (210):

CH₂═CFCF₂O(CF(CF₃)CF₂O)_(m)(CF(CF₃))_(n)—X²¹¹

wherein m is an integer of 0 to 5; n is an integer of 1 to 3; X²¹¹ is acyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom,a bromine atom, or —CH₂OH; and

a monomer represented by the following formula (220):

CR²²¹R²²²═CR²²³—Z²²¹—CR²²⁴═CR²²⁵R²²⁶

wherein R²²¹, R²²², R²²³, R²²⁴, R²²⁵, and R²²⁶ are the same as ordifferent from each other, and are each a hydrogen atom or a C1-C5 alkylgroup; Z²²¹ is a C1-C18 linear or branched alkylene group optionallycontaining an oxygen atom, a C3-C18 cycloalkylene group, an at leastpartially fluorinated C1-C10 alkylene or oxyalkylene group, or a(per)fluoropolyoxyalkylene group which is represented by the followingformula:

-(Q)_(p)-CF₂O—(CF₂CF₂O)_(m)(CF₂O)_(n)—CF₂-(Q)_(p)-

(wherein Q is an alkylene group or an oxyalkylene group; p is 0 or 1;and m/n is 0.2 to 5) and which has a molecular weight of 500 to 10000.

X¹⁸³ and X¹⁹³ are each preferably an iodine atom. R_(f) ¹⁸¹ and R_(f)¹⁹¹ are each preferably a C1-C5 perfluoroalkylene group. R¹⁸¹ ispreferably a hydrogen atom. X²⁰¹ is preferably a cyano group, analkoxycarbonyl group, an iodine atom, a bromine atom, or —CH₂I. X²¹¹ ispreferably a cyano group, an alkoxycarbonyl group, an iodine atom, abromine atom, or —CH₂OH.

An example of the fluorinated vinyl heterocycle is a fluorinated vinylheterocycle represented by the following formula (230):

wherein X²³¹ and X²³² are each individually F, Cl, a methoxy group, or afluorinated methoxy group; and Y²³¹ is represented by the followingformula Y²³² or Y²³³.

wherein Z²³¹ and Z²³² are each individually F or a C1-C3 fluorinatedalkyl group.

The monomer giving a crosslinking site preferably includes at least oneselected from the group consisting of CF₂═CFOCF₂CF(CF₃)OCF₂CF₂CN,

-   CF₂═CFOCF₂CF(CF₃)OCF₂CF₂COOH, CF₂═CFOCF₂CF(CF₃)OCF₂CF₂COOCH₃,-   CF₂═CFOCF₂CF(CF₃)OCF₂CF₂CH₂I, CF₂═CFOCF₂CF₂CH₂I,-   CH₂═CFCF₂OCF(CF₃)CF₂OCF(CF₃)CN, CH₂═CFCF₂OCF(CF₃)CF₂OCF(CF₃)COOH,-   CH₂═CFCF₂OCF(CF₃)CF₂OCF(CF₃)COOCH₃,-   CH₂═CFCF₂OCF(CF₃)CF₂OCF(CF₃)CH₂OH, CH₂═CHCF₂CF₂I,    CH₂═CH(CF₂)₂CH═CH₂,-   CH₂═CH(CF₂)₆CH═CH₂, and CF₂═CFO(CF₂)₅CN, more preferably at least    one selected from the group consisting of CF₂═CFOCF₂CF(CF₃)OCF₂CF₂CN    and CF₂═CFOCF₂CF₂CH₂I.

In the above step, the fluoromonomer may be polymerized with afluorine-free monomer. An example of the fluorine-free monomer is ahydrocarbon monomer reactive with the fluoromonomer. Examples of thehydrocarbon monomer include alkenes such as ethylene, propylene,butylene, and isobutylene; alkyl vinyl ethers such as ethyl vinyl ether,propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, andcyclohexyl vinyl ether; vinyl esters such as vinyl acetate, vinylpropionate, vinyl n-butyrate, vinyl isobutyrate, vinyl valerate, vinylpivalate, vinyl caproate, vinyl caprylate, vinyl caprate, vinylversatate, vinyl laurate, vinyl myristate, vinyl palmitate, vinylstearate, vinyl benzoate, vinyl para-t-butylbenzoate, vinylcyclohexanecarboxylate, monochlorovinyl acetate, vinyl adipate, vinylacrylate, vinyl methacrylate, vinyl crotonate, vinyl sorbate, vinylcinnamate, vinyl undecylenate, vinyl hydroxyacetate, vinylhydroxypropionate, vinyl hydroxybutyrate, vinyl hydroxyvalerate, vinylhydroxyisobutyrate, and vinyl hydroxycyclohexanecarboxylate; alkyl allylethers such as ethyl allyl ether, propyl allyl ether, butyl allyl ether,isobutyl allyl ether, and cyclohexyl allyl ether; and alkyl allyl esterssuch as ethyl allyl ester, propyl allyl ester, butyl allyl ester,isobutyl allyl ester, and cyclohexyl allyl ester.

The fluorine-free monomer may also be a functional group-containinghydrocarbon monomer. Examples of the functional group-containinghydrocarbon monomer include hydroxy alkyl vinyl ethers such ashydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinylether, hydroxyisobutyl vinyl ether, and hydroxycyclohexyl vinyl ether;carboxyl group-containing fluorine-free monomers such as itaconic acid,fumaric acid, fumaric anhydride, crotonic acid, maleic acid, and maleicanhydride; glycidyl group-containing fluorine-free monomers such asglycidyl vinyl ether and glycidyl allyl ether; amino group-containingfluorine-free monomers such as aminoalkyl vinyl ether and aminoalkylallyl ether; and amide group-containing fluorine-free monomers such as(meth)acrylamide and methylol acrylamide.

In the above step, polymerization of one or two or more of the abovefluoromonomers can provide particles of a desired fluoropolymer.

In the production method of the invention, the presence of at least oneof the above surfactants can efficiently provide a fluoropolymer. In theproduction method of the invention, two or more of the surfactants maybe used as the surfactants, and a compound having a surfactant functionother than the above surfactants may be used together as long as thecompound is volatile or is allowed to remain in an article such as amolded article formed from the fluoropolymer.

In the production method of the invention, the polymerization is alsopreferably performed in the presence of a nonionic surfactant. Thenonionic surfactant preferably includes at least one selected from thegroup consisting of:

a compound represented by the following formula (240):

Rf²⁴¹—(X²⁴¹)_(n)-Y²⁴¹

wherein Rf²⁴¹ is a partially fluorinated alkyl group or perfluorinatedalkyl group containing 1 to 12 carbon atoms; n is 0 or 1; X²⁴¹ is —O—,—COO—, or —OCO—; Y²⁴¹ is —(CH₂)_(p)H, —(CH₂)_(p)OH, or—(OR²⁴¹)_(q)(OR²⁴²)_(r)OH; p is an integer of 1 to 12; q is an integerof 1 to 12; r is an integer of 0 to 12; R²⁴¹ and R²⁴² are each analkylene group containing 2 to 4 carbon atoms, with R²⁴¹ and R²⁴² beingdifferent from each other;

a block polymer represented by the following formula (250):

H(OR²⁵¹)_(u)(OR²⁵²)_(v)OH

wherein R²⁵¹ and R²⁵² are each an alkylene group containing 1 to 4carbon atoms; u and v are each an integer of 1 to 5, with R²⁵¹ and R²⁵²being different from each other;

a nonionic surfactant containing a hydrophobic group composed of aC8-C20 hydrocarbon group and a hydrophilic group composed of apolyalkylene oxide in the molecule; and

a silicon compound represented by the following formula (260):

R²⁶¹ _(m)—Si—(OR²⁶²)_(4-m)

wherein R²⁶¹ is an alkyl group containing 1 to 12 carbon atoms; R²⁶² isan alkyl group containing 1 to 4 carbon atoms; and m is an integer of 1to 3.

Specific examples of the block polymer represented by the formula (250)include block polymers containing at least two segments selected fromthe group consisting of polyoxyethylene, polyoxypropylene, andpolyoxybutylene. Examples thereof includepolyoxyethylene-polyoxypropylene block polymers andpolyoxyethylene-polyoxybutylene block polymers. Not only A-B blockpolymers but also A-B-A block polymers are preferred. More preferably,use of a polyoxyethylene-polyoxypropylene block polymer or apolyoxypropylene-polyoxyethylene-polyoxypropylene block polymer can leadto a stable fluoropolymer dispersion having a high concentration. Inorder to reduce generation of agglomerates due to re-agglomeration, thepolyoxyethylene segment preferably represents 10 to 50%. In order toprovide a fluoropolymer dispersion having low viscosity, thepolyoxyethylene segment preferably represents 20 to 40%. Thepolyoxyethylene segment may have a molecular weight of, but not limitedto, 1000 to 7000 g/mol. In particular, the polyoxyethylene segmenthaving a molecular weight of 2500 to 6500 g/mol can lead to a dispersionhaving low viscosity and excellent dispersibility.

In the production method of the invention, a nucleating agent may beused. The nucleating agent is preferably used in an amount appropriatelyselected in accordance with the type of the nucleating agent. Forexample, the amount thereof is 1000 ppm or less, more preferably 500 ppmor less, still more preferably 100 ppm or less, particularly preferably50 ppm or less, more particularly preferably 10 ppm or less, relative tothe aqueous medium.

The presence of the nucleating agent can lead to a fluoropolymer havinga smaller primary particle size than in the case of polymerization inthe absence of the nucleating agent.

Examples of the nucleating agent include perfluoropolyether (PFPE) acidand salts thereof, and hydrocarbon-containing surfactants other than thesurfactants (a) and (b). The nucleating agent is preferably free from anaromatic ring, and is preferably an aliphatic compound.

The nucleating agent is preferably added before addition of apolymerization initiator or simultaneously with addition of apolymerization initiator. Still, it may be added during thepolymerization to control the particle size distribution.

The perfluoropolyether (PFPE) acid or a salt thereof may have any chainstructure in which the oxygen atoms in the main chain of the moleculeare separated by C1-C3 saturated carbon fluoride groups. Two or morecarbon fluoride groups may be present in the molecule. Typicalstructures thereof contain any of the repeating units represented by thefollowing formulae:

(—CFCF₃—CF₂—O—)_(n)  (VII)

(—CF₂—CF₂—CF₂—O—)_(n)  (VIII)

(—CF₂—CF₂—O—)_(n)—(—CF₂—O—)_(m)  (IX)

(—CF₂—CFCF₃—O—)_(n)—(—CF₂—O—)_(m)  (X)

These structures are described in Kasai, J. Appl. Polymer Sci.,57,797(1995). As disclosed in this document, the PFPE acid or a saltthereof may contain a carboxylic acid group or a salt thereof at one oreach end. The PFPE acid or a salt thereof may also contain a sulfonicacid, a phosphonic acid group, or a salt thereof at one or each end. ThePFPE acid or a salt thereof may contain different groups at therespective ends. For a monofunctional PFPE, the other end of themolecule is usually perfluorinated, but may contain a hydrogen orchlorine atom. The PFPE acid or a salt thereof contains at least twoether oxygen atoms, preferably at least four ether oxygen atoms, stillmore preferably at least six ether oxygen atoms. Preferably at least onecarbon fluoride group separating ether oxygen atoms, more preferably atleast two such carbon fluoride groups, each contain two or three carbonatoms. Still more preferably, at least 50% of the carbon fluoride groupsseparating ether oxygen atoms contain two or three carbon atoms. Alsopreferably, the PFPE acid or a salt thereof contains at least 15 carbonatoms in total. For example, the minimum value of n or n+m in therepeating unit structure is preferably at least 5. Two or more of thePFPE acids and salts thereof containing an acid group at one or each endmay be used in the production method of the invention. The PFPE acid ora salt thereof preferably has a number average molecular weight of lessthan 6000 g/mol.

The hydrocarbon-containing surfactant is preferably added in an amountof 40 ppm or less, more preferably 30 ppm or less, still more preferably20 ppm or less, relative to the aqueous medium. The lower limit thereofis preferably 0.01 ppm, more preferably 0.1 ppm, still more preferably1.0 ppm.

The hydrocarbon-containing surfactant includes nonionic surfactants andcationic surfactants, including siloxane surfactants such as thosedisclosed in U.S. Pat. No. 7,897,682 B (Brothers et al.) and U.S. Pat.No. 7,977,438 B (Brothers et al.).

The hydrocarbon-containing surfactant is preferably a nonionichydrocarbon surfactant. In other words, the nucleating surfactant ispreferably a nonionic hydrocarbon surfactant. The nonionic hydrocarbonsurfactant is preferably free from an aromatic moiety.

Examples of the nonionic hydrocarbon surfactant include polyoxyethylenealkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkylesters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters,glycerol esters, and derivatives thereof. Specifically, examples of thepolyoxyethylene alkyl ethers include polyoxyethylene lauryl ether,polyoxyethylene cetyl ether, polyoxyethylene stearyl ether,polyoxyethylene oleyl ether, and polyoxyethylene behenyl ether; examplesof the polyoxyethylene alkyl phenyl ethers include polyoxyethylene nonylphenyl ether and polyoxyethylene octyl phenyl ether; examples of thepolyoxyethylene alkyl esters include polyethylene glycol monolaurylate,polyethylene glycol monooleate, and polyethylene glycol monostearate;examples of the sorbitan alkyl esters include polyoxyethylene sorbitanmonolaurylate, polyoxyethylene sorbitan monopalmitate, polyoxyethylenesorbitan monostearate, and polyoxyethylene sorbitan monooleate; examplesof the polyoxyethylene sorbitan alkyl esters include polyoxyethylenesorbitan monolaurylate, polyoxyethylene sorbitan monopalmitate, andpolyoxyethylene sorbitan monostearate; examples of the glycerol estersinclude glycerol monomyristate, glycerol monostearate, and glycerolmonooleate. Examples of the derivatives thereof include polyoxyethylenealkylamines, polyoxyethylene alkyl phenyl-formaldehyde condensates, andpolyoxyethylene alkyl ether phosphates. Particularly preferred arepolyoxyethylene alkyl ethers and polyoxyethylene alkyl esters. Examplesof such ethers and esters include those having an HLB value of 10 to 18.Specific examples thereof include polyoxyethylene lauryl ether (EO: 5 to20, EO means an ethylene oxide unit), polyethylene glycol monostearate(EO: 10 to 55), and polyethylene glycol monooleate (EO: 6 to 10).

Preferred examples of the nonionic hydrocarbon surfactant include octylphenol ethoxylates such as the following Triton® X series available fromDow Chemical Co.

Triton®

X15: n=1.5 (avg)

X45: n=4.5 (avg)

Preferred examples of the nonionic hydrocarbon surfactant also includebranched alcohol ethoxylates such as the following Tergitol® 15-S seriesavailable from Dow Chemical Co. and branched secondary alcoholethoxylates such as the following Tergitol® TMN series also availablefrom Dow Chemical Co.

Tergitol®

TMN-6: n=8 (avg)

TMN-10: n=11 (avg)

TMN-100: n=10 (avg)

Ethylene oxide/propylene oxide copolymers such as Tergitol® L seriessurfactants available from Dow Chemical Company are also useful as theabove nonionic hydrocarbon surfactants.

Examples of preferred nonionic hydrocarbon surfactants in the group ofuseful ones include the following bifunctional block copolymers such asPluronic® R series available from BASF.

Pluronic®

31R1: m=26 (avg), n=8 (avg)

17R2: m=14 (avg), n=9 (avg)

10R5: m=8 (avg), n=22 (avg)

25R4: m=22 (avg), n=23 (avg)

Preferred nonionic hydrocarbon surfactants in another group includetridecyl alcohol alkoxylates such as Iconol® TDA series available fromBASF Corp.

Iconol®

TDA-6: n=6 (avg)

TDA-9: n=9 (avg)

TDA-10: n=19 (avg)

The cationic surfactants are also useful as nucleating surfactants.Typical cationic surfactants contain a positively charged hydrophilicportion such as an alkyl ammonium halide, including alkyl ammoniumbromide, and a hydrophobic portion such as a long-chain fatty acid.

Nucleating surfactants in another group to be used includehydrocarbon-containing siloxane surfactants, preferably hydrocarbonsurfactants. When the hydrocarbyl groups are to be replaced by a halogensuch as fluorine, they are completely replaced by hydrogen atoms, andthus these siloxane surfactants can also be regarded as hydrocarbonsurfactants. In other words, a monovalent substituent of the hydrocarbylgroup is hydrogen. The nucleating surfactant is preferably a hydrocarbonsiloxane containing a nonionic moiety, i.e., a nonionic hydrocarbon(siloxane) surfactant.

In the case of using TFE as a fluoromonomer to producepolytetrafluoroethylene (PTFE) as a fluoropolymer,(polyfluoroalkyl)ethylene (a) and/or a comonomer (b) having a monomerreactivity ratio rTFE in copolymerization with TFE of 0.1 to 8 are mixedin the emulsion polymerization system in an amount of 0.001 to 0.01% bymass relative to the final PTFE yield at the start of emulsionpolymerization of TFE. Thereby, a PTFE aqueous emulsion can be producedwhich has high stability enough to maintain properties such asprocessability and moldability in the following steps and which iscapable of providing a molded article having high heat resistance.

The reactivity ratio can be determined as follows. Comonomers in avariety of proportions are copolymerized with TFE and the composition ofthe resulting polymer immediately after the start is determined. Then,based on the composition, the reactivity ratio is calculated by theFineman-Ross equation.

The copolymerization is performed using 3600 g of deionized deaeratedwater, 1000 ppm of perfluorooctanoic acid relative to the water, and 100g of paraffin wax contained in a 6.0-L-capacity stainless steelautoclave at a pressure of 0.78 MPa and a temperature of 70° C. Acomonomer in an amount of 0.05 g, 0.1 g, 0.2 g, 0.5 g, or 1.0 g is putinto the reactor, and then 0.072 g of ammonium persulfate (20 ppmrelative to the water) is added thereto. To maintain the polymerizationpressure at 0.78 MPa, TFE is continually fed thereinto. When the amountof TFE fed reached 1000 g, stirring is stopped and the pressure isreleased until the pressure in the reactor decreases to the atmosphericpressure. The system is cooled down and then the paraffin wax isremoved. Thereby, an aqueous dispersion containing the resulting polymeris obtained. The aqueous dispersion is stirred so that the resultingpolymer precipitates, and the polymer is dried at 150° C. Thecomposition in the resulting polymer is calculated by appropriatecombination of NMR, FT-IR, elemental analysis, and X-ray fluorescenceanalysis in accordance with the types of the monomers.

In the production method of the invention, a reactive surfactant may beused together with the surfactant. The reactive surfactant is a compoundcontaining at least one vinyl group and having a surfactant function.Examples thereof include:

a surfactant represented by the following formula (270a):

CF₂═CF—(CF₂)_(n271a)-Y²⁷¹

wherein n271a is an integer of 1 to 10; Y²⁷¹ is —SO₃M²⁷¹ or —COOM²⁷¹;M²⁷¹ is H, NH₄, or an alkali metal;

a surfactant represented by the following formula (270b):

CF₂═CF—(CF₂C(CF₃)F)_(n271b)—Y²⁷¹

wherein n271b is an integer of 1 to 5; and Y²⁷¹ is defined as describedabove;

a surfactant represented by the following formula (270c):

CF₂═CF—O—(CFX²⁷¹)_(n271c)—Y²⁷¹

wherein X²⁷¹ is F or CF₃; n271c is an integer of 1 to 10; and Y²⁷¹ isdefined as described above;

a surfactant represented by the following formula (270d):

CF₂═CF—O—(CF₂CFX²⁷¹O)_(n271a)—CF₂CF₂—Y²⁷¹

wherein n271d is an integer of 1 to 10; and Y²⁷¹ and X²⁷¹ are defined asdescribed above; and

a surfactant represented by the following formula (270e):

CX²⁷² ₂═CFCF₂—O—(CF(CF₃)CF₂O)_(n271e)—CF(CF₃)—Y²⁷¹

wherein X²⁷²s are the same as each other, and are each F or H; n271e is0 or an integer of 1 to 10; and Y²⁷¹ is defined as described above.

In addition to the surfactant and a compound having a surfactantfunction used as appropriate, an additive may also be used to stabilizethe compounds in the production method of the invention. Examples of theadditive include a buffer, a pH adjuster, a stabilizing aid, and adispersion stabilizer.

The stabilizing aid is preferably paraffin wax, fluorine-based oil, afluorine-based solvent, silicone oil, or the like. One stabilizing aidmay be used alone, or two or more stabilizing aids may be used incombination. The stabilizing aid is more preferably paraffin wax. Theparaffin wax may be in the form of liquid, semi-solid, or solid at roomtemperature, and is preferably a saturated hydrocarbon containing 12 ormore carbon atoms. The paraffin wax usually preferably has a meltingpoint of 40° C. to 65° C., more preferably 50° C. to 65° C.

The stabilizing aid is preferably used in an amount of 0.1 to 12% bymass, more preferably 0.1 to 8% by mass, relative to the mass of theaqueous medium used. Preferably, the stabilizing aid is sufficientlyhydrophobic, to be completely separated from the PTFE aqueous emulsionafter emulsion polymerization of TFE, and does not serve as acontaminating component.

In the production method of the invention, the polymerization isperformed by charging a polymerization reactor with an aqueous medium,the surfactant, monomers, and optionally other additives, stirring thecontents of the reactor, maintaining the reactor at a predeterminedpolymerization temperature, adding a predetermined amount of apolymerization initiator, and thereby initiating the polymerizationreaction. After the polymerization reaction is initiated, the componentssuch as the monomers, the polymerization initiator, a chain transferagent, and the surfactant may additionally be added in accordance withthe purposes thereof. The surfactant may be added after thepolymerization reaction is initiated.

The polymerization is usually performed at a polymerization temperatureof 5° C. to 120° C. and a polymerization pressure of 0.05 to 10 MPaG.The polymerization temperature and the polymerization pressure aredecided as appropriate in accordance with the types of the monomersused, the molecular weight of the target fluoropolymer, and the reactionrate.

The surfactant is preferably added in a total amount of 0.0001 to 10% bymass relative to 100% by mass of the aqueous medium. The lower limitthereof is more preferably 0.001% by mass, while the upper limit thereofis more preferably 1% by mass. Less than 0.0001% by mass of thesurfactant may cause insufficient dispersibility. More than 10% by massof the surfactant may fail to give the effects corresponding to itsamount; on the contrary, such an amount of the surfactant may cause areduction in the polymerization rate or even stop the reaction. Theamount of the compound is appropriately decided in accordance withfactors such as the types of the monomers used and the molecular weightof the target fluoropolymer.

The polymerization initiator may be any one capable of generatingradicals within the above polymerization temperature range, and a knownoil-soluble and/or water-soluble polymerization initiator may be used.The polymerization initiator may be combined with a reducing agent, forexample, to serve as a redox and initiate the polymerization. Theconcentration of the polymerization initiator is decided as appropriatein accordance with the types of the monomers, the molecular weight ofthe target fluoropolymer, and the reaction rate.

The polymerization initiator may be an oil-soluble radicalpolymerization initiator or a water-soluble radical polymerizationinitiator.

The oil-soluble radical polymerization initiator may be a knownoil-soluble peroxide. Typical examples thereof include dialkylperoxycarbonates such as diisopropyl peroxydicarbonate and di-sec-butylperoxydicarbonate; peroxy esters such as t-butyl peroxyisobutyrate andt-butyl peroxypivalate; and dialkyl peroxides such as di-t-butylperoxide, as well as di[perfluoro (or fluorochloro) acyl] peroxides suchas di(ω-hydro-dodecafluoroheptanoyl)peroxide,di(ω-hydro-tetradecafluoroheptanoyl)peroxide,di(ω-hydro-hexadecafluorononanoyl)peroxide,di(perfluorobutyryl)peroxide, di(perfluorovaleryl)peroxide,di(perfluorohexanoyl)peroxide, di(perfluoroheptanoyl)peroxide,di(perfluorooctanoyl)peroxide, di(perfluorononanoyl)peroxide,di(ω-chloro-hexafluorobutyryl)peroxide,di(o-chloro-decafluorohexanoyl)peroxide,di(ω-chloro-tetradecafluorooctanoyl)peroxide,ω-hydro-dodecafluoroheptanoyl-o-hydrohexadecafluorononanoyl-peroxide,ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide,ω-hydrododecafluoroheptanoyl-perfluorobutyryl-peroxide,di(dichloropentafluorobutanoyl)peroxide,di(trichlorooctafluorohexanoyl)peroxide,di(tetrachloroundecafluorooctanoyl)peroxide,di(pentachlorotetradecafluorodecanoyl)peroxide, anddi(undecachlorodotoriacontafluorodocosanoyl)peroxide.

The water-soluble radical polymerization initiator may be a knownwater-soluble peroxide, and examples thereof include ammonium salts,potassium salts, and sodium salts of persulfuric acid, perboric acid,perchloric acid, perphosphoric acid, and percarbonic acid, t-butylpermaleate, and t-butyl hydroperoxide. A reducing agent such as asulfite or a sulfurous acid salt may be contained together, and theamount thereof may be 0.1 to 20 times the amount of the peroxide.

For example, in the case of polymerization at a low temperature of 30°C. or lower, the polymerization initiator used is preferably a redoxinitiator that is a combination of an oxidizing agent and a reducingagent. Examples of the oxidizing agent include persulfates, organicperoxides, potassium permanganate, manganese triacetate, ammonium ceriumnitrate, and bromic acid salts. Examples of the reducing agent includesulfites, bisulfites, bromic acid salts, diimines, and oxalic acid.Examples of the persulfates include ammonium persulfate and potassiumpersulfate. Examples of the sulfites include sodium sulfite and ammoniumsulfite. In order to increase the decomposition rate of the initiator,the combination of a redox initiator may preferably contain a coppersalt or an iron salt. An example of the copper salt is copper(II)sulfate and an example of the iron salt is iron(II) sulfate.

Examples of the redox initiator include potassium permanganate/oxalicacid, ammonium persulfate/bisulfite/iron(II) sulfate, ammoniumpersulfate/sulfite/iron(II) sulfate, ammonium persulfate/sulfite,ammonium persulfate/iron(II) sulfate, manganese triacetate/oxalic acid,ammonium cerium nitrate/oxalic acid, bromic acid salt/sulfite, andbromic acid salt/bisulfite. Preferred are potassium permanganate/oxalicacid and ammonium persulfate/sulfite/iron(II) sulfate. In the case ofusing a redox initiator, either an oxidizing agent or a reducing agentis put into a polymerization tank in advance and the other iscontinually or intermittently added thereto to initiate thepolymerization. For example, in the case of potassiumpermanganate/oxalic acid, preferably, oxalic acid is put into apolymerization tank and potassium permanganate is continually addedthereto.

The polymerization initiator may be added in any amount, and theinitiator in an amount that does not significantly decrease thepolymerization rate (e.g., several parts per million in water) or moremay be added at once in the early stage of polymerization, or may beadded successively or continually. The upper limit thereof falls withina range where the reaction temperature is allowed to increase while thepolymerization reaction heat is removed through the device surfaces. Theupper limit thereof is preferably within a range where thepolymerization reaction heat can be removed through the device surfaces.

The aqueous medium is a reaction medium in which the polymerizationprogresses, and is a liquid that contains water. The aqueous medium maybe any medium that contains water, and it may be one containing waterand, for example, any of fluorine-free organic solvents such asalcohols, ethers, and ketones, and/or fluorinated organic solventshaving a boiling point of 40° C. or lower.

In the polymerization, any of known chain transfer agents, radicalscavengers, and decomposers may be added in accordance with the purposesto control the polymerization rate and the molecular weight.

Examples of the chain-transfer agent include esters such as dimethylmalonate, diethyl malonate, methyl acetate, ethyl acetate, butylacetate, and dimethyl succinate, as well as isopentane, methane, ethane,propane, isobutane, methanol, ethanol, isopropanol, acetone, mercaptans,halogenated hydrocarbons such as carbon tetrachloride, and cyclohexane.

The chain-transfer agent may be a bromine compound or an iodinecompound. An example of a polymerization method using a bromine compoundor an iodine compound is a method of performing polymerization of afluoromonomer in an aqueous medium substantially in the absence ofoxygen and in the presence of a bromine compound or an iodine compound(iodine transfer polymerization). Representative examples of the brominecompound or the iodine compound to be used include compounds representedby the following formula:

R^(a)I_(x)Br_(y)

(wherein x and y are each an integer of 0 to 2 and satisfy 1≤x+y≤2; andR^(a) is a C1-C16 saturated or unsaturated fluorohydrocarbon orchlorofluorohydrocarbon group, or a C1-C3 hydrocarbon group, each ofwhich optionally contains an oxygen atom). The presence of a brominecompound or an iodine compound enables introduction of iodine or bromineinto the polymer, and such iodine or bromine introduced can serve as acrosslinking point.

Examples of the iodine compound include 1,3-diiodoperfluoropropane,2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane,1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane,1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane,1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane,diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF₂Br₂,BrCF₂CF₂Br, CF₃CFBrCF₂Br, CFClBr₂, BrCF₂CFClBr, CFBrClCFClBr,BrCF₂CF₂CF₂Br, BrCF₂CFBrOCF₃, 1-bromo-2-iodoperfluoroethane,1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane,2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1,2-bromo-4-iodoperfluorobutene-1, and a monoiodo- andmonobromo-substitution product, diiodo- and monobromo-substitutionproduct, and (2-iodoethyl)- and (2-bromoethyl)-substitution product ofbenzene. These compounds may be used alone or in any combination.

In order to achieve good polymerization reactivity, crosslinkability,and easy availability, for example, 1,4-diiodoperfluorobutane,1,6-diiodoperfluorohexane, or 2-iodoperfluoropropane is preferably used.

The chain transfer agent is usually used in an amount of 1 to 50000 ppm,preferably 1 to 20000 ppm, relative to the whole amount of thefluoromonomer fed.

The chain transfer agent may be added to the reaction container at oncebefore initiation of the polymerization, may be added at once afterinitiation of the polymerization, may be added in multiple portionsduring the polymerization, or may be added continually during thepolymerization.

The method for producing a fluoropolymer may be a method for producing afluoropolymer including: a step (I) of polymerizing the fluoromonomer inan aqueous medium in the presence of the surfactant to provide anaqueous dispersion of particles of a fluorine-containing polymer (A);and a step (II) of seed-polymerizing the fluoromonomer to the particlesof the fluorine-containing polymer (A) in the aqueous dispersion of theparticles of the fluorine-containing polymer (A).

Examples of the fluoropolymer suitably produced by the production methodof the invention include a TFE polymer in which TFE is the monomerhaving the highest mole fraction (hereinafter, “most numerous monomer”)among the monomers in the polymer, a VDF polymer in which VDF is themost numerous monomer, and a CTFE polymer in which CTFE is the mostnumerous monomer.

The TFE polymer may suitably be a TFE homopolymer, or may be a copolymercontaining (1) TFE, (2) one or two or more fluorine-containing monomerseach of which is different from TFE and contains 2 to 8 carbon atoms, inparticular VDF, HFP, or CTFE, and (3) a different monomer. Examples ofthe different monomer (3) include fluoro(alkyl vinyl ethers) containinga C1-C5, particularly C1-C3 alkyl group; fluorodioxoles; perfluoroalkylethylenes; and ω-hydroperfluoroolefins.

The TFE polymer may be a copolymer of TFE and one or two or morefluorine-free monomers. Examples of the fluorine-free monomers includealkenes such as ethylene and propylene; vinyl esters; and vinyl ethers.The TFE polymer may be a copolymer of TFE, one or two or morefluorine-containing monomers containing 2 to 8 carbon atoms, and one ortwo or more fluorine-free monomers.

The VDF polymer may suitably be a VDF homopolymer (PVDF), or may be acopolymer containing (1) VDF, (2) one or two or more fluoroolefins eachof which is different from VDF and contains 2 to 8 carbon atoms, inparticular TFE, HFP, or CTFE, and (3) a perfluoro(alkyl vinyl ether)containing a C1-C5, particularly C1-C3 alkyl group.

The CTFE polymer may suitably be a CTFE homopolymer, or may be acopolymer containing (1) CTFE, (2) one or two or more fluoroolefins eachof which is different from CTFE and contains 2 to 8 carbon atoms, inparticular TFE or HFP, and (3) a perfluoro(alkyl vinyl ether) containinga C1-C5, particularly C1-C3 alkyl group.

The CTFE polymer may be a copolymer of CTFE and one or two or morefluorine-free monomers. Examples of the fluorine-free monomers includealkenes such as ethylene and propylene; vinyl esters; and vinyl ethers.

The fluoropolymer produced by the production method of the invention maybe vitreous, plastic, or elastomeric. Such a fluoropolymer is amorphousor partially crystallized, and can be subjected to compression firing,melt fabrication, or non-melt fabrication.

The production method of the invention can suitably provide (I) nonmelt-processible fluororesins, including tetrafluoroethylene polymers(TFE polymers (PTFE)); (II) melt-fabricable fluororesins, includingethylene/TFE copolymers (ETFE), TFE/HFP copolymers (FEP),TFE/perfluoro(alkyl vinyl ether) copolymers (e.g., PFA, MFA), TFE/VDFcopolymers, and electrolyte polymer precursors; and (III)fluoroelastomers, including TFE/propylene copolymers,TFE/propylene/third monomer copolymers (the third monomer may be VDF,HFP, CTFE, fluoroalkyl vinyl ether, or the like), TFE/fluoroalkyl vinylether copolymers; HFP/ethylene copolymers, HFP/ethylene/TFE copolymers;PVDF; thermoplastic elastomers such as VDF/HFP copolymers, HFP/ethylenecopolymers, and VDF/TFE/HFP copolymers (THV); and fluorine-containingsegmented polymers disclosed in JP S61-49327 B.

The fluoropolymer is preferably a fluororesin, more preferably afluororesin having a fluorine substitution percentage, calculated by thefollowing formula, of 50% or higher, still more preferably a fluororesinhaving a fluorine substitution percentage of higher than 50%, furthermore preferably a fluororesin having a fluorine substitution percentageof 55% or higher, still further more preferably a fluororesin having afluorine substitution percentage of 60% or higher, much further morepreferably a fluororesin having a fluorine substitution percentage of75% or higher, particularly preferably a fluororesin having a fluorinesubstitution percentage of 80% or higher, most preferably a fluororesinhaving a fluorine substitution percentage of 90 to 100%, i.e., aperfluororesin.

Fluorine substitution percentage (%)=(number of fluorine atoms bindingto any of carbon atoms constituting fluoropolymer)/[(number of hydrogenatoms binding to any of carbon atoms constituting fluoropolymer)+(numberof fluorine atoms and chlorine atoms binding to any of carbon atomsconstituting fluoropolymer)]×100  (Formula)

The perfluororesin is more preferably a fluororesin having a fluorinesubstitution percentage of 95 to 100%, still more preferably PTFE, FEP,or PFA, particularly preferably PTFE.

The fluoropolymer may have a core-shell structure. An example of thefluoropolymer having a core-shell structure is a modified PTFE includinga core of high-molecular-weight PTFE and a shell of alower-molecular-weight PTFE or a modified PTFE in the molecule. Anexample of such a modified PTFE is a PTFE disclosed in JP 2005-527652 T.

The core-shell structure may have any of the following structures.

Core: TFE homopolymer Shell: TFE homopolymer Core: modified PTFE Shell:TFE homopolymer Core: modified PTFE Shell: modified PTFE Core: TFEhomopolymer Shell: modified PTFE Core: low-molecular-weight PTFE Shell:high-molecular-weight PTFE Core: high-molecular-weight PTFE Shell:low-molecular-weight PTFE

In the fluoropolymer having a core-shell structure, the lower limit ofthe proportion of the core is preferably 0.5% by mass, more preferably1.0% by mass, still more preferably 3.0% by mass, particularlypreferably 5.0% by mass, most preferably 10.0% by mass. The upper limitof the proportion of the core is preferably 99.5% by mass, morepreferably 99.0% by mass, still more preferably 97.0% by mass,particularly preferably 95.0% by mass, most preferably 90.0% by mass.

In the fluoropolymer having a core-shell structure, the lower limit ofthe proportion of the shell is preferably 0.5% by mass, more preferably1.0% by mass, still more preferably 3.0% by mass, particularlypreferably 5.0% by mass, most preferably 10.0% by mass. The upper limitof the proportion of the shell is preferably 99.5% by mass, morepreferably 99.0% by mass, still more preferably 97.0% by mass,particularly preferably 95.0% by mass, most preferably 90.0% by mass.

In the fluoropolymer having a core-shell structure, the core or theshell may have a structure of two or more layers. For example, thefluoropolymer may have a trilayer structure including a core centerportion of a modified PTFE, a core outer layer portion of a TFEhomopolymer, and a shell of a modified PTFE. An example of afluoropolymer having such a trilayer structure is a PTFE disclosed in WO2006/054612.

The non melt-processible fluororesins (I), the melt-fabricablefluororesins (II), and the fluoroelastomers (III) suitably produced bythe production method of the invention are preferably produced in thefollowing manner.

(I) Non Melt-Processible Fluororesins

In the production method of the invention, polymerization of TFE isusually performed at a polymerization temperature of 10° C. to 150° C.and a polymerization pressure of 0.05 to 5 MPaG.

In an embodiment, the polymerization reaction is initiated by feedingpure water into a pressure-resistant reaction container equipped with astirrer, deoxidizing the system, feeding TFE, increasing the temperatureto a predetermined level, and adding a polymerization initiator. If thepressure decreases as the reaction progresses, additional TFE is fedcontinually or intermittently to maintain the initial pressure. When theamount of TFE fed reaches a predetermined level, feeding is stopped. TFEin the reaction container is purged and the temperature is reduced toroom temperature, whereby the reaction is completed. Additional TFE maybe added continually or intermittently to prevent a pressure decrease.

In production of the TFE polymer (PTFE), any of known modifying monomersmay be used together. The TFE polymer as used herein is a concept thatencompasses not only a TFE homopolymer but also a non melt-processiblecopolymer of TFE and a modifying monomer (hereinafter, referred to as a“modified PTFE”).

Examples of the modifying monomer include perhaloolefins such as HFP andCTFE; fluoro(alkyl vinyl ethers) containing a C1-C5, particularly C1-3alkyl group; cyclic fluorinated monomers such as fluorodioxole;perhaloalkyl ethylenes; and ω-hydroperhaloolefins. The modifying monomermay be fed at once in an initial stage, or may be fed in portionscontinually or intermittently in accordance with the purpose and themanner of TFE feeding.

The modified PTFE usually has a modifying monomer content within therange of 0.001 to 2.0% by mass. The lower limit of the modifying monomercontent is more preferably 0.01% by mass, still more preferably 0.05% bymass. The upper limit of the modifying monomer content is morepreferably 1.0% by mass, still more preferably 0.5% by mass,particularly preferably 0.3% by mass.

In production of the TFE polymer, the surfactant can be used within theuse range described for the production method of the invention. Thesurfactant may be added in any concentration within the above range, andis usually added at a critical micelle concentration (CMC) or lower ininitiating the polymerization. Too large an amount of the surfactantadded may cause generation of needle-shaped particles having a largeaspect ratio and gelling of the aqueous dispersion, impairing thestability. The lower limit of the amount of the surfactant used ispreferably 0.0001% by mass, more preferably 0.001% by mass, still morepreferably 0.01% by mass, particularly preferably 0.1% by mass, relativeto the aqueous medium. The upper limit of the surfactant is preferably10% by mass, more preferably 5% by mass, still more preferably 3% bymass, particularly preferably 2% by mass, relative to the aqueousmedium.

The surfactant may be added to a reaction container at once beforeinitiation of the polymerization, may be added at once after initiationof the polymerization, may be added in multiple portions during thepolymerization, or may be added continually during the polymerization.

In production of the TFE polymer, the polymerization initiator used maybe an organic peroxide such as a persulfate (e.g., ammonium persulfate),disuccinic acid peroxide, or diglutaric acid peroxide alone or in theform of an mixture thereof. An organic peroxide may be used togetherwith a reducing agent such as sodium sulfite to form a redox system.During the polymerization, a radical scavenger such as hydroquinone orcatechol may be added or a decomposer for peroxides such as ammoniumsulfite may be added to control the radical concentration in the system.

The redox polymerization initiator is preferably a redox initiator thatis a combination of an oxidizing agent and a reducing agent. Examples ofthe oxidizing agent include persulfates, organic peroxides, potassiumpermanganate, manganese triacetate, ammonium cerium nitrate, and bromicacid salts. Examples of the reducing agent include sulfites, bisulfites,bromic acid salts, diimines, and oxalic acid. Examples of thepersulfates include ammonium persulfate and potassium persulfate.Examples of the sulfites include sodium sulfite and ammonium sulfite. Inorder to increase the decomposition rate of the initiator, thecombination of a redox initiator may preferably contain a copper salt oran iron salt. An example of the copper salt is copper(II) sulfate and anexample of the iron salt is iron(II) sulfate.

Examples of the redox initiator include potassium permanganate/oxalicacid, ammonium persulfate/bisulfite/iron(II) sulfate, ammoniumpersulfate/sulfite/iron(II) sulfate, ammonium persulfate/sulfite,ammonium persulfate/iron(II) sulfate, manganese triacetate/oxalic acid,ammonium cerium nitrate/oxalic acid, bromic acid salt/sulfite, andbromic acid salt/bisulfite. Preferred are potassium permanganate/oxalicacid and ammonium persulfate/sulfite/iron(II) sulfate. In the case ofusing a redox initiator, either an oxidizing agent or a reducing agentis put into a polymerization tank in advance and the other iscontinually or intermittently added thereto to initiate thepolymerization. For example, in the case of potassiumpermanganate/oxalic acid, preferably, oxalic acid is put into apolymerization tank and potassium permanganate is continually addedthereto.

In production of the TFE polymer, a known chain transfer agent may beused. Examples thereof include saturated hydrocarbons such as methane,ethane, propane, and butane, halogenated hydrocarbons such aschloromethane, dichloromethane, and difluoroethane, alcohols such asmethanol and ethanol, and hydrogen. The chain transfer agent ispreferably one in a gas state at normal temperature and normal pressure.

The chain transfer agent is usually used in an amount of 1 to 10000 ppm,preferably 1 to 5000 ppm, relative to the whole amount of TFE fed.

In production of the TFE polymer, a saturated hydrocarbon that issubstantially inert to the reaction, that is in a liquid state under theabove reaction conditions, and that contains 12 or more carbon atoms maybe used as a dispersion stabilizer for the reaction system in an amountof 2 to 10 parts by mass relative to 100 parts by mass of the aqueousmedium. A buffer such as ammonium carbonate or ammonium phosphate may beadded to control the pH during the reaction.

At completion of the polymerization for the TFE polymer, an aqueousdispersion having a solid content of 1.0 to 70% by mass and an averageprimary particle size of 50 to 500 nm can be obtained. The aqueousdispersion contains the surfactant and the fluoropolymer. The presenceof the surfactant enables production of an aqueous dispersion containingparticles of the TFE polymer having a particle size as small as 0.5 μmor smaller.

The lower limit of the solid content is preferably 5% by mass, morepreferably 8% by mass. The upper limit thereof may be, but is notlimited to, 40% by mass or 35% by mass.

The lower limit of the average primary particle size is preferably 100nm, more preferably 150 nm. The upper limit thereof is preferably 400nm, more preferably 350 nm.

Agglomerating the aqueous dispersion can lead to fine powder. Theaqueous dispersion of the TFE polymer can be formed into fine powderthrough agglomeration, washing, and drying. The resulting fine powdermay be used in a variety of applications. Agglomeration of the aqueousdispersion of the TFE polymer is usually performed by diluting theaqueous dispersion obtained by polymerization for polymer latex, forexample, with water to a polymer concentration of 5 to 20% by mass,optionally adjusting the pH to a neutral or alkaline level, and stirringthe polymer more vigorously than during the reaction in a containerequipped with a stirrer. The agglomeration may be performed understirring while a water-soluble organic compound such as methanol oracetone, an inorganic salt such as potassium nitrate or ammoniumcarbonate, or an inorganic acid such as hydrochloric acid, sulfuricacid, or nitric acid is added as a coagulating agent. The agglomerationmay be continually performed using a device such as an inline mixer.

In wastewater generated by the agglomeration, the TFE polymer in thenon-agglomerated form is preferably present at a low concentration so asto achieve high productivity, more preferably at a concentration of lessthan 0.4% by mass, particularly preferably less than 0.3% by mass.

Before or during the agglomeration, a pigment for coloring or filler forimprovement of mechanical properties may be added. Thereby, pigment- orfiller-containing fine powder of a TFE polymer in which the pigment orthe filler is uniformly blended therein.

Wet powder obtained by the agglomeration of the TFE polymer in theaqueous dispersion is usually dried by vacuum, high-frequency waves, hotair, or the like while the wet powder is less fluidized, preferably leftto stand. Friction between the particles especially at high temperaturewill usually adversely affect the TFE polymer in the form of finepowder. This is because the particles of such a TFE polymer are easilyformed into fibrils even with a small shearing force and lose theoriginal, stable particulate structure.

The drying is performed at a drying temperature of 10° C. to 250° C.,preferably 100° C. to 200° C.

The resulting fine powder of the TFE polymer is preferred for molding.Examples of preferred applications thereof include tubes for hydraulicsystems or fuel systems of aircraft or automobiles, flexible hoses forchemicals or vapors, and electric wire coating.

The aqueous dispersion of the TFE polymer obtained by the polymerizationmay be mixed with a nonionic surfactant so that the aqueous dispersionis stabilized and more concentrated. In accordance with the purpose,preferably, such an aqueous dispersion may be mixed with organic orinorganic filler to form a composition and used in a variety ofapplications. The composition, when applied to a metal or ceramicsubstrate, can provide a film having non-stickiness, a low coefficientof friction, and excellent gloss, smoothness, abrasion resistance,weather resistance, and heat resistance. Thus, the composition issuitable for coating of rolls and cooking utensils and impregnation ofglass cloth.

The aqueous dispersion may be formed into an organosol of the TFEpolymer. The organosol can contain the TFE polymer and an organicsolvent. Examples of the organic solvent include ether-based solvents,ketone-based solvents, alcohol-based solvents, amide-based solvents,ester-based solvents, aliphatic hydrocarbon-based solvents, aromatichydrocarbon-based solvents, and halogenated hydrocarbon-based solvents.Preferably used are N-methyl-2-pyrrolidone and dimethyl acetamide. Theorganosol may be prepared by the method disclosed in WO 2012/002038, forexample.

The aqueous dispersion of the TFE polymer or the fine powder of the TFEpolymer is also preferably used as a processing aid. When used as aprocessing aid, the aqueous dispersion or the fine powder is mixed witha host polymer, for example, to improve the melt strength of the hostpolymer in melt fabrication and to improve the mechanical strength,electric properties, incombustibility, anti-drop performance duringcombustion, and slidability of the resulting polymer.

The aqueous dispersion of the TFE polymer or the fine powder of the TFEpolymer is also preferably used as a binding agent for batteries or usedfor dustproof applications.

The aqueous dispersion of the TFE polymer or the fine powder of the TFEpolymer is also preferably combined with a resin other than the TFEpolymer to form a processing aid before use. The aqueous dispersion orthe fine powder is suitable as a material of the PTFEs disclosed in JPH11-49912 A, U.S. Pat. No. 5,804,654 B, JP H11-29679 A, and JP 2003-2980A. The processing aid containing the aqueous dispersion or the finepowder is nothing inferior to the processing aids disclosed in the abovedocuments.

The aqueous dispersion of the TFE polymer is also preferably mixed withan aqueous dispersion of a melt-fabricable fluororesin so that thecomponents agglomerate to form co-agglomerated powder. Theco-agglomerated powder is suitable as a processing aid.

Examples of the melt-fabricable fluororesin include FEP, PFA, ETFE, andethylene/TFE/HFP copolymers (EFEPs). Preferred is FEP.

The aqueous dispersion also preferably contains a melt-fabricablefluororesin. Examples of the melt-fabricable fluororesin include FEP,PFA, ETFE, and EFEP. The aqueous dispersion containing themelt-fabricable fluororesin may be used as a coating material. Themelt-fabricable fluororesin enables sufficient fusion of the TFE polymerparticles, improving the film-formability and giving gloss to theresulting film.

The co-agglomerated powder may be added to a fluorine-free resin in theform of powder, pellets, or emulsion. In order to achieve sufficientmixing of the resins, the addition is preferably performed by a knownmethod such as extrusion kneading or roll kneading under a shearingforce.

The aqueous dispersion of the TFE polymer is also preferably used as adust control agent. The dust control agent may be used in a method inwhich the dust control agent is mixed with a dust-generating substanceand the mixture is affected by a compression-shear effect at atemperature of 20° C. to 200° C. to form fibrils of the TFE polymer,thereby reducing dust of dust-generating substances, such as the methodsdisclosed in JP 2827152 B and JP 2538783 B.

The aqueous dispersion of the TFE polymer can suitably be used for thedust control agent composition disclosed in WO 2007/004250, and can alsosuitably be used for a method of dust control treatment disclosed in WO2007/000812.

The dust control agent can suitably be used for dust control treatmentin the field of construction materials, for powdery quicklime, Portlandcement, anhydrous gypsum, and granulated blast furnace slag powder usedin the field of soil stabilizers and the field of solidificationmaterials, in the field of fertilizers, in the field of reclamation ofash and hazardous materials, in the field of explosion protection, inthe field of cosmetics, for pet toilet sand typified by cat litter, andsolid particulate substances generating heat by hydration reactions,typified by alkaline earth metal oxides, alkaline earth metal peroxides,calcium carbide, calcium phosphide water, calcium aluminate, and calciumsilicate.

The aqueous dispersion of the TFE polymer is also preferably used as amaterial for producing TFE polymer fibers by a dispersion spinningmethod. The dispersion spinning method is a method in which the aqueousdispersion of the TFE polymer and an aqueous dispersion of a matrixpolymer are mixed and the mixture is extruded to form an intermediatefiber structure, and then the intermediate fiber structure is fired todecompose the matrix polymer and sinter the TFE polymer particles,thereby providing TFE polymer fibers.

The surfactant may be used to produce a high-molecular-weight PTFE. Inother words, even without a conventional fluorinated surfactant, theproduction method of the invention using the surfactant can surprisinglyproduce a PTFE having a molecular weight equivalent to that of a PTFEobtained by a production method using such a conventional fluorinatedsurfactant.

The high-molecular-weight PTFE powder obtainable by the polymerizationis also useful as a material of a PTFE stretched article (PTFE porousarticle). For example, a stretched article is obtainable bypaste-extruding the high-molecular-weight PTFE powder mixed with anextrusion aid, optionally rolling the workpiece, drying the workpiece toremove the extrusion aid, and stretching the workpiece in at least onedirection. Stretching enables easy formation of fibrils of PTFE,resulting in a PTFE stretched article including nodes and fibers. ThisPTFE stretched article is also a porous article having a high porosity.

This stretched article is also preferably in the form of a film, a tube,fibers, or rods.

The stretched article in the form of a film (PTFE stretched film or PTFEporous film) can be formed by stretching by a known PTFE stretchingmethod.

Preferably, roll-stretching a sheet-shaped or rod-shaped paste extrudatein an extruding direction can provide a uniaxially stretched film.

Further stretching in a transverse direction using a tenter, forexample, can provide a biaxially stretched film.

Prebaking treatment is also preferably performed before stretching.

This PTFE stretched article is a porous article having a high porosity,and can suitably be used as a filter material for a variety ofmicrofiltration membranes such as air filters and chemical filters and asupport member for polymer electrolyte membranes.

The PTFE stretched article is also useful as a material of products usedin the textile field, the medical treatment field, the electrochemicalfield, the sealant field, the air filter field, the ventilation/internalpressure adjustment field, the liquid filter field, and the consumergoods field.

The following provides examples of specific applications.

Electrochemical Field

Examples of the applications in this field include prepregs fordielectric materials, EMI-shielding materials, and heat conductivematerials. More specifically, examples thereof include printed circuitboards, electromagnetic interference shielding materials, insulatingheat conductive materials, and insulating materials.

Sealant Field

Examples of the applications in this field include gaskets, packings,pump diaphragms, pump tubes, and sealants for aircraft.

Air Filter Field

Examples of the applications in this field include ULPA filters (forproduction of semiconductors), HEPA filters (for hospitals and forproduction of semiconductors), cylindrical cartridge filters (forindustries), bag filters (for industries), heat-resistant bag filters(for exhaust gas treatment), heat-resistant pleated filters (for exhaustgas treatment), SINBRAN filters (for industries), catalyst filters (forexhaust gas treatment), absorbent-attached filters (for HDD embedment),absorbent-attached vent filters (for HDD embedment), vent filters (forHDD embedment, for example), filters for cleaners (for cleaners),general-purpose multilayer felt materials, cartridge filters for GT (forinterchangeable items for GT), and cooling filters (for housings ofelectronic devices).

Ventilation/Internal Pressure Adjustment Field

Examples of the applications in this field include materials for freezedrying such as containers for freeze drying, ventilation materials forautomobiles for electronic circuits and lamps, applications relating tocontainers such as container caps, protective ventilation for electronicdevices, including small devices such as tablet terminals and mobilephone terminals, and ventilation for medical treatment.

Liquid Filter Field

Examples of the applications in this field include liquid filters forsemiconductors (for production of semiconductors), hydrophilic PTFEfilters (for production of semiconductors), filters for chemicals (forliquid chemical treatment), filters for pure water production lines (forproduction of pure water), and back-washing liquid filters (fortreatment of industrial drainage).

Consumer Goods Field

Examples of the applications in this field include clothes, cable guides(movable wires for motor bikes), clothes for motor cyclists, cast liners(medical supporters), filters for cleaners, bagpipes (musicalinstrument), cables (signal cables for guitars), and strings (for stringinstrument).

Textile Field

Examples of the applications in this field include PTFE fibers (fibermaterials), machine threads (textiles), weaving yarns (textiles), andropes.

Medical Treatment Field

Examples of the applications in this field include implants (extendingarticles), artificial blood vessels, catheters, general surgicaloperations (tissue reinforcing materials), products for head and neck(dura mater alternatives), oral health (tissue regenerative medicine),and orthopedics (bandages).

The surfactant may also be used to produce a low-molecular-weight PTFE.

The low-molecular-weight PTFE may be produced by polymerization, or maybe produced by a known method (e.g., thermolysis, radiolysis) ofreducing the molecular weight of a high-molecular-weight PTFE obtainedby polymerization.

A low-molecular-weight PTFE having a molecular weight of 600000 or less(also referred to as PTFE micropowder) has excellent chemical stabilityand a very low surface energy, and is less likely to generate fibrils.Thus, such a low-molecular-weight PTFE can suitably be used as anadditive for improving the lubricity and the texture of the film surfacein production of plastics, inks, cosmetics, coating materials, greases,parts of office automation equipment, and toners (e.g., see JPH10-147617 A).

A low-molecular-weight PTFE may be obtained by dispersing apolymerization initiator and the surfactant in an aqueous medium in thepresence of a chain transfer agent, and then polymerizing TFE alone orTFE and a monomer copolymerizable with TFE.

In the case of using as powder a low-molecular-weight PTFE obtained bythe polymerization, the aqueous dispersion may be subjected toagglomeration to provide powder particles.

The high-molecular-weight PTFE as used herein means a PTFE having nonmelt-processability and a fibrillation ability. The low-molecular-weightPTFE as used herein means a PTFE having melt-fabricability and nofibrillation ability.

The non melt-processability means a feature of a polymer that the meltflow rate thereof cannot be measured at a temperature higher than thecrystal melting point in conformity with ASTM D1238 and D2116.

The presence or absence of the fibrillation ability can be determined by“paste extrusion”, a representative method of molding a“high-molecular-weight PTFE powder” which is a powder (fine powder) of aTFE emulsion polymer. The ability of a high-molecular-weight PTFE powderto be paste-extruded is owing to the fibrillation ability thereof. If anon-sintered molded article obtained by paste extrusion showssubstantially no strength or elongation (for example, if it shows anelongation of 0% and is broken when stretched), it can be considered asnon-fibrillatable.

The high-molecular-weight PTFE preferably has a standard specificgravity (SSG) of 2.130 to 2.280. The standard specific gravity isdetermined by the water replacement method in conformity with ASTM D792using a sample prepared in conformity with ASTM D4895-89. The “highmolecular weight” as used herein means that the standard specificgravity is within the above range.

The low-molecular-weight PTFE has a melt viscosity of 1×10² to 7×10⁵Pa·s at 380° C. The “low molecular weight” as used herein means that themelt viscosity is within the above range.

The high-molecular-weight PTFE has a melt viscosity significantly higherthan that of the low-molecular-weight PTFE, and the melt viscositythereof is difficult to measure accurately. The melt viscosity of thelow-molecular-weight PTFE is measurable, but the low-molecular-weightPTFE has difficulty in providing a molded article to be used inmeasurement of the standard specific gravity. Thus, the standardspecific gravity thereof is difficult to measure accurately.Accordingly, in the invention, the standard specific gravity is used asan index of the molecular weight of the high-molecular-weight PTFE,while the melt viscosity is used as an index of the molecular weight ofthe low-molecular-weight PTFE. For both the high-molecular-weight PTFEand the low-molecular-weight PTFE, no measurement methods for directlyspecifying the molecular weight have been known so far.

The high-molecular-weight PTFE preferably has a peak temperature of 333°C. to 347° C., more preferably 335° C. to 345° C. Thelow-molecular-weight PTFE preferably has a peak temperature of 322° C.to 333° C., more preferably 324° C. to 332° C. The peak temperature isthe temperature corresponding to the maximum value on a heat-of-fusioncurve with a temperature-increasing rate of 10° C./min using adifferential scanning calorimeter (DSC) for a PTFE which has never beenheated up to 300° C. or higher.

Preferably, the high-molecular-weight PTFE has at least one endothermicpeak in a temperature range of 333° C. to 347° C. on a heat-of-fusioncurve with a temperature-increasing rate of 10° C./min using adifferential scanning calorimeter (DSC) for a PTFE which has never beenheated up to 300° C. or higher, and has an enthalpy of fusion of 62mJ/mg or higher at 290° C. to 350° C. calculated from the heat-of-fusioncurve.

The PTFE fine powder obtained by the use of the surfactant may be usedto produce unsintered tape (green tape).

The surfactant, decomposition products and by-products of thesurfactant, and residual monomers may be collected from wastewatergenerated in the agglomeration or the washing and/or off gas generatedin the drying, and then may be purified, whereby the surfactant, thedecomposition products and by-products of the surfactant, and theresidual monomers may be reused. The collection and the purification maybe performed by known methods, although not limited thereto. Forexample, they may be performed by the methods disclosed in JP2011-520020 T.

(II) Melt-Fabricable Fluororesins

(1) In the production method of the invention, the polymerization forFEP is preferably performed at a polymerization temperature of 10° C. to150° C. and a polymerization pressure of 0.3 to 6.0 MPaG.

The FEP preferably has a monomer composition ratio (% by mass) ofTFE:HFP=(60 to 95):(5 to 40), more preferably (85 to 92):(8 to 15). TheFEP may be modified with a perfluoro(alkyl vinyl ether) as a thirdcomponent within a range of 0.1 to 2% by mass of all monomers.

In the polymerization for FEP, the surfactant may be used within the userange of the production method of the invention, and is usually added inan amount of 0.0001 to 10% by mass relative to 100% by mass of theaqueous medium.

In the polymerization for FEP, the chain transfer agent used ispreferably cyclohexane, methanol, ethanol, propanol, ethane, propane,butane, pentane, hexane, carbon tetrachloride, chloroform, methylenechloride, methyl chloride, or the like, and the pH buffer used ispreferably ammonium carbonate, disodium hydrogen phosphate, or the like.

The aqueous dispersion of FEP obtained by the production method of theinvention may optionally be subjected to post-treatment such asconcentration, and then the concentrate may be dried and powdered, andthe powder may be melt-extruded into pellets. The aqueous medium in theFEP aqueous dispersion may contain an additive such as a nonionicsurfactant, if necessary, and may contain a water-soluble organicsolvent such as a water-soluble alcohol or may be free from awater-soluble organic solvent.

The melt extrusion may be performed under any appropriately selectedextrusion conditions usually capable of providing pellets.

The FEP obtained by the production method of the invention may containan end group such as —CF₃ or —CF₂H on at least one of the polymer mainchain or a polymer side chain. Still, the FEP preferably contains asmall amount of a thermally unstable group (hereinafter, referred to asan “unstable end group”) such as —COOH, —CH₂OH, —COF, —CF═CF—, —CONH₂,or —COOCH₃, or contains no such a group.

The unstable end group is chemically unstable, and thus not only reducesthe heat resistance of the resin but also increases the attenuation ofthe resulting electric wire.

The production method of the invention preferably provides a polymersuch that the polymer at completion of the polymerization contains 50 orless unstable end groups and —CF₂H end groups in total per 1×10⁶ carbonatoms. The number of such groups is more preferably less than 20, stillmore preferably 5 or less, per 1×10⁶ carbon atoms. Neither unstable endgroups nor —CF₂H end groups are present and every end group may be a—CF₃ end group.

Unstable end groups and —CF₂H end groups may be fluorinated into —CF₃end groups and thereby stabilized. An example of the fluorination methodis, but not limited to, a method of exposing the polymer to a fluorineradical source that generates fluorine radicals under fluorinationconditions. Examples of the fluorine radical source include fluorinegas, CoF₃, AgF₂, UF₆, OF₂, N₂F₂, CF₃OF, and halogen fluorides such asIF₅ and ClF₃. Preferred is a method of bringing a fluorination gas andFEP obtained in the invention into direct contact with each other. Inorder to control the reaction, the contact is preferably performed usinga diluted fluorine gas having a fluorine gas concentration of 10 to 50%by mass. The diluted fluorine gas is obtainable by diluting fluorine gaswith an inert gas such as nitrogen gas or argon gas. The fluorine gastreatment may be performed at a temperature of 100° C. to 250° C. Thetreatment temperature is not limited to this range and may beappropriately adjusted in accordance with the situation. The fluorinegas treatment is preferably performed by feeding a diluted fluorine gasinto the reactor continually or intermittently. This fluorinationtreatment may be performed on dry powder after the polymerization or onmelt-extruded pellets.

The FEP obtained by the production method of the invention has goodmoldability and is less likely to cause molding failure, as well ashaving good properties such as heat resistance, chemical resistance,solvent resistance, insulation, and electric properties.

The FEP powder may be produced by a method of drying the FEP obtained bythe production method of the invention to powder the FEP.

The powder may be fluorinated. The fluorinated powder may be produced bya method of feeding a fluorine gas to the powder obtained by the methodof producing the powder to fluorinate the powder.

The FEP pellets may be produced by a method of pelletizing the FEPobtained by the production method of the invention.

The pellets may be fluorinated. The fluorinated pellets may be producedby a method of feeding a fluorine gas to the pellets obtained by themethod of producing the pellets to fluorinate the pellets.

Thus, this FEP may be used in production of a variety of molded articlessuch as coating materials for electric wires, foamed electric wires,cables, and wires, tubes, films, sheets, and filaments.

(2) In the production method of the invention, the polymerization for aTFE/perfluoro(alkyl vinyl ether) copolymer such as PFA or MFA is usuallypreferably performed at a polymerization temperature of 10° C. to 100°C. and a polymerization pressure of 0.3 to 6.0 MPaG.

The TFE/perfluoro(alkyl vinyl ether) copolymer preferably has a monomercomposition ratio (mol %) of TFE:perfluoro(alkyl vinyl ether)=(90 to99.7):(0.3 to 10), more preferably (97 to 99):(1 to 3). Theperfluoro(alkyl vinyl ether) used is preferably one represented by theformula: CF₂═CFORf⁴, wherein Rf⁴ is a C1-C6 perfluoroalkyl group.

In the polymerization for the TFE/perfluoro(alkyl vinyl ether)copolymer, the surfactant may be used within the use range of theproduction method of the invention, and is usually preferably added inan amount of 0.0001 to 10% by mass relative to 100% by mass of theaqueous medium.

In the polymerization for the TFE/perfluoro(alkyl vinyl ether)copolymer, the chain transfer agent used is preferably cyclohexane,methanol, ethanol, propanol, propane, butane, pentane, hexane, carbontetrachloride, chloroform, methylene chloride, methyl chloride, methane,ethane, or the like, and the pH buffer used is preferably ammoniumcarbonate, disodium hydrogen phosphate, or the like.

The aqueous dispersion of the TFE/perfluoro(alkyl vinyl ether) copolymersuch as PFA or MFA obtained by the production method of the inventionmay optionally be subjected to post-treatment such as concentration, andthen the concentrate may be dried and powdered, and the powder may bemelt-extruded into pellets. The aqueous medium in the aqueous dispersionmay contain an additive such as a nonionic surfactant, if necessary, andmay contain a water-soluble organic solvent such as a water-solublealcohol or may be free from a water-soluble organic solvent.

The melt extrusion may be performed under any appropriately selectedextrusion conditions usually capable of providing pellets.

In order to improve the heat resistance of the copolymer and toreinforce a chemical permeation reducing effect of a molded article, thecopolymer is preferably subjected to a fluorine gas treatment.

The fluorine gas treatment is performed by bringing fluorine gas intocontact with a chemical permeation reducing agent. Still, a reactionwith fluorine generates a large amount of heat, so that fluorine ispreferably diluted with an inert gas such as nitrogen. Such a fluorinegas/inert gas mixture has a fluorine content of 1 to 100% by weight,preferably 10 to 25% by weight. The treatment is performed at atreatment temperature of 150° C. to 250° C., preferably 200° C. to 250°C. and the fluorine gas treatment duration is 3 to 16 hours, preferably4 to 12 hours. The fluorine gas treatment is performed at a gas pressureof 1 to 10 atm, preferably atmospheric pressure. In the case of using areactor at atmospheric pressure, the fluorine gas/inert gas mixture iscontinually passed through the reactor. This causes conversion ofunstable ends of the copolymer into —CF₃ ends, making the copolymerthermally stable.

The copolymer and the composition thereof may be molded by compressionmolding, transfer molding, extrusion molding, injection molding, blowmolding, or the like similar to conventional PFA.

Such a molding technique can provide a desired molded article. Examplesof the molded article include sheets, films, packings, round bars,square bars, pipes, tubes, round tanks, square tanks, tanks, wafercarriers, wafer boxes, beakers, filter housings, flowmeters, pumps,valves, cocks, connectors, nuts, electric wires, and heat-resistantelectric wires.

Preferred among these are tubes, pipes, tanks, connectors, and the liketo be used for a variety of chemical reaction devices, semiconductormanufacturing devices, and acidic or alkaline chemical feeding deviceseach requiring chemical impermeability.

The aqueous dispersion of a TFE/perfluoro(alkyl vinyl ether) copolymersuch as PFA or MFA may be appropriately mixed with a nonionicsurfactant, and optionally polyethersulfone, polyamide-imide, and/orpolyimide and metal powder are dissolved or dispersed in an organicsolvent. Thereby, a primer composition can be obtained. This primercomposition can be used in a method of applying a fluororesin to a metalsurface. This method includes applying the primer composition to a metalsurface, applying a melt-fabricable fluororesin composition to theresulting primer layer, and firing the melt-fabricable fluororesincomposition layer together with the primer layer.

(3) In the production method of the invention, the polymerization forETFE is preferably performed at a polymerization temperature of 10° C.to 100° C. and a polymerization pressure of 0.3 to 2.0 MPaG.

The ETFE preferably has a monomer composition ratio (mol %) ofTFE:ethylene=(50 to 99):(50 to 1). The ETFE may be modified with a thirdmonomer within a range of 0 to 20% by mass of all monomers. Thecomposition ratio thereof is preferably TFE:ethylene:third monomer=(63to 94):(27 to 2):(1 to 10). The third monomer preferably includes any ofperfluorobutyl ethylene, perfluorobutyl ethylene,3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooct-1-ene,2,3,3,4,4,5,5-heptafluoro-1-pentene (CH₂═CFCF₂CF₂CF₂H), and2-trifluoromethyl-3,3,3-trifluoropropene ((CF₃)₂C═CH₂).

In the polymerization for ETFE, the surfactant may be used within theuse range of the production method of the invention, and is usuallyadded in an amount of 0.0001 to 10% by mass relative to 100% by mass ofthe aqueous medium.

In the polymerization for ETFE, the chain transfer agent used ispreferably cyclohexane, methanol, ethanol, propanol, ethane, propane,butane, pentane, hexane, carbon tetrachloride, chloroform, methylenechloride, methyl chloride, or the like.

The aqueous dispersion of ETFE obtained by the production method of theinvention may optionally be subjected to post-treatment such asconcentration, and then the concentrate may be dried and powdered, andthe powder may be melt-extruded into pellets. The aqueous medium in theaqueous dispersion may contain an additive such as a nonionicsurfactant, if necessary, and may contain a water-soluble organicsolvent such as a water-soluble alcohol or may be free from awater-soluble organic solvent.

The melt extrusion may be performed under any appropriately selectedextrusion conditions usually capable of providing pellets.

The ETFE may be extrusion-molded into a sheet. In other words, powder orpellets of ETFE in a molten state may be continuously extruded through adie and then cooled to provide a sheet-shaped molded article. The ETFEmay be mixed with an additive.

The additive used as appropriate may be a known one. Specific examplesthereof include ultraviolet absorbers, photostabilizers, antioxidants,infrared absorbers, flame retarders, flame-retardant filler, organicpigments, inorganic pigments, and dyes. In order to achieve excellentweather resistance, an inorganic additive is preferred.

The additive in the ETFE sheet is preferably present in an amount of 20%by mass or less, particularly preferably 10% by mass or less, relativeto the whole mass of the ETFE sheet.

The ETFE sheet has excellent mechanical strength and appearance, andthus can suitably be used for film materials (e.g., roof materials,ceiling materials, outer wall materials, inner wall materials, andcoating materials) of film-structured buildings (e.g., sportsfacilities, gardening facilities, and atriums).

In addition to the film materials of film-structured buildings, the ETFEsheet is also useful for outdoor boards (e.g., noise-blocking walls,windbreak fences, breakwater fences, roof panels of carports, shoppingarcades, footpath walls, and roof materials), shatter-resistant windowfilms, heat-resistant waterproof sheets, building materials (e.g., tentmaterials of warehouse tents, film materials for shading, partial roofmaterials for skylights, window materials alternative to glass, filmmaterials for flame-retardant partitions, curtains, outer wallreinforcement, waterproof films, anti-smoke films, non-flammabletransparent partitions, road reinforcement, interiors (e.g., lighting,wall surfaces, and blinds), exteriors (e.g., tents and signboards)),living and leisure goods (e.g., fishing rods, rackets, golf clubs, andscreens), automobile materials (e.g., hoods, damping materials, andbodies), aircraft materials, shipment materials, exteriors of homeappliances, tanks, container inner walls, filters, film materials forconstruction works, electronic materials (e.g., printed circuit boards,circuit boards, insulating films, and release films), surface materialsfor solar cell modules, mirror protection materials for solar thermalenergy, and surface materials for solar water heaters.

The ETFE pellets have excellent heat resistance, and thus are suitableas a material of coating materials for electric wires.

Examples of the electric wires include cables and wires. Examples of theelectric wire in the invention include coaxial cables, high-frequencycables, flat cables, and heat-resistant cables.

(4) The production method of the invention may be used to produce anelectrolyte polymer precursor. In the production method of theinvention, the polymerization for the electrolyte polymer precursor ispreferably performed at a polymerization temperature of 10° C. to 100°C. and a polymerization pressure of 0.1 to 2.0 MPaG. The electrolytepolymer precursor contains a vinyl ether monomer as described below andcan be converted into an ion-exchangeable polymer through a hydrolysistreatment.

An example of the vinyl ether monomer to be used for the electrolytepolymer precursor is a fluoromonomer represented by the formula (150):

CF₂═CF—O—(CF₂CFY¹⁵¹—O)_(n)—(CFY¹⁵²)_(m)-A¹⁵¹

(wherein Y¹⁵¹ is a fluorine atom, a chlorine atom, a —SO₂F group, or aperfluoroalkyl group, the perfluoroalkyl group optionally containingether oxygen and a —SO₂F group; n is an integer of 0 to 3; n Y¹⁵'s arethe same as or different from each other; Y¹⁵² is a fluorine atom, achlorine atom, or a —SO₂F group; m is an integer of 1 to 5; m Y¹⁵²s arethe same as or different from each other; A¹⁵¹ is —SO₂X¹⁵¹, —COZ¹⁵¹, or—POZ¹⁵²Z¹⁵³; X¹⁵¹ is F, Cl, Br, I, —OR¹⁵¹, or —NR¹⁵²R¹⁵³; Z¹⁵¹, Z¹⁵²,and Z¹⁵³ are the same as or different from each other, and are each—NR¹⁵⁴R¹⁵⁵ or —OR¹⁵⁶; R¹⁵¹, R¹⁵², R¹⁵³, R¹⁵⁴, R¹⁵⁵, and R¹⁵⁶ are thesame as or different from each other, and are each H, ammonium, analkali metal, or an alkyl group, aryl group, or sulfonyl-containinggroup optionally containing a fluorine atom). The electrolyte polymerprecursor preferably has a monomer composition ratio (mol %) ofTFE:vinyl ether=(50 to 99):(50 to 1), more preferably TFE:vinylether=(50 to 93):(50 to 7).

The electrolyte polymer precursor may be modified with a third monomerwithin a range of 0 to 20% by mass of all monomers. Examples of thethird monomer include multifunctional monomers such as CTFE, vinylidenefluoride, perfluoroalkyl vinyl ether, and divinylbenzene.

The electrolyte polymer precursor thereby obtained may be molded into afilm, followed by hydrolysis using an alkali solution and a treatmentusing a mineral acid, and thereby used as a polymer electrolyte membranefor fuel cells, electrolysis devices, and redox flow batteries.

The electrolyte polymer precursor may be hydrolyzed using an alkalisolution while the dispersed state thereof is maintained, therebyproviding an electrolyte polymer dispersion. This dispersion may be thenheated up to 120° C. or higher in a pressurized container and therebydissolved in, for example, a solvent mixture of water and an alcohol,i.e., converted into a solution state.

The solution thereby obtained may be used as a binder for electrodes.Also, the solution may be combined with a variety of additives and castto form a film, and this film may be used for antifouling films andorganic actuators.

(5) TFE/VDF Copolymer

In the production method of the invention, the polymerization for theTFE/VDF copolymer may be performed at any polymerization temperature,such as 0° C. to 100° C. The polymerization pressure is selected asappropriate in accordance with the other polymerization conditions suchas the polymerization temperature, and is usually 0 to 9.8 MPaG.

The TFE/VDF copolymer preferably has a monomer composition ratio (mol %)of TFE:VDF=(5 to 90):(95 to 10). The TFE/VDF copolymer may be modifiedwith a third monomer within a range of 0 to 50 mol % of all monomers.The composition ratio thereof is preferably TFE:ethylene:thirdmonomer=(30 to 85):(10 to 69.9):(0.1 to 10).

The third monomer is preferably a monomer represented by the followingformula:

CX¹¹X¹²═CX¹³(CX¹⁴X¹⁵)_(n11)X¹⁶

(wherein X¹¹ to X¹⁶ are the same as or different from each other, andare each H, F, or Cl; and n11 is an integer of 0 to 8) other than TFEand VDF, or a monomer represented by the following formula:

CX²¹X²²═CX²³—O(CX²⁴X²⁵)_(n21)X²⁶

(wherein X²¹ to X²⁶ are the same as or different from each other, andare each H, F, or Cl; and n21 is an integer of 0 to 8).

The third monomer may be a fluorine-free ethylenic monomer. In order tomaintain the heat resistance and the chemical resistance, thefluorine-free ethylenic monomer is preferably selected from ethylenicmonomers containing 6 or less carbon atoms. Examples thereof includeethylene, propylene, 1-butene, 2-butene, vinyl chloride, vinylidenechloride, alkyl vinyl ethers (e.g., methyl vinyl ether, ethyl vinylether, and propyl vinyl ether), maleic acid, itaconic acid, 3-butenoicacid, 4-pentenoic acid, vinylsulfonic acid, acrylic acid, andmethacrylic acid.

In the polymerization for the TFE/VDF copolymer, the surfactant may beused within the use range of the production method of the invention, andis usually added in an amount of 0.0001 to 5% by mass relative to 100%by mass of the aqueous medium.

The TFE/VDF copolymer obtained by the polymerization may be brought intocontact with a nitrogen compound that can generate ammonia water,ammonia gas, or ammonia, and thereby may be amidated.

The TFE/VDF copolymer obtained by the above method may also preferablybe used as a material for providing TFE/VDF copolymer fibers by aspinning-drawing method. The spinning-drawing method is a method inwhich the TFE/VDF copolymer is melt-spun and then cool-solidified toprovide undrawn yarn, and the undrawn yarn is passed through a heatingcylinder and thereby drawn, so that TFE/VDF copolymer fibers areobtained.

The TFE/VDF copolymer may be dissolved in an organic solvent to providea solution of the TFE/VDF copolymer. Examples of the organic solventinclude nitrogen-containing organic solvents such asN-methyl-2-pyrrolidone, N,N-dimethyl acetamide, and dimethyl formamide;ketone-based solvents such as acetone, methyl ethyl ketone,cyclohexanone, and methyl isobutyl ketone; ester-based solvents such asethyl acetate and butyl acetate; ether-based solvents such astetrahydrofuran and dioxane; and low-boiling-point general-purposeorganic solvents such as solvent mixtures of any of these. The solutionmay be used as a binder for batteries.

The aqueous dispersion of the TFE/VDF copolymer may preferably be usedto coat a porous substrate formed from a polyolefin resin to provide acomposite porous film. The aqueous dispersion may also preferablycontain inorganic particles and/or organic particles dispersed thereinand be used to coat a porous substrate to provide a composite porousfilm. The composite porous film thereby obtained may be used as aseparator for lithium secondary batteries.

The powder of the melt-fabricable fluororesin is suitably used as apowdery coating material. When applied to a substrate, the powderycoating material containing the melt-fabricable fluororesin powder canprovide a film having a smooth surface. The melt-fabricable fluororesinpowder having an average particle size of not smaller than 1 μm butsmaller than 100 μm is particularly suitable as a powdery coatingmaterial used for electrostatic coating. The melt-fabricable fluororesinpowder having an average particle size of 100 μm or greater and 1000 μmor smaller is particularly suitable as a powdery coating material usedfor rotational coating or rotational molding.

The melt-fabricable fluororesin powder can be produced by a method inwhich the melt-fabricable fluororesin obtained by the production methodof the invention is dried and powdered. The method for producing themelt-fabricable fluororesin powder is also one aspect of the invention.

(III) Fluoroelastomers

In the production method of the invention, the polymerization reactionfor the fluoroelastomer is initiated by feeding pure water and thesurfactant into a pressure-resistant reaction container equipped with astirrer, deoxidizing the system, feeding the monomers, increasing thetemperature to a predetermined level, and adding a polymerizationinitiator. The pressure decreases as the reaction progresses, additionalmonomers are fed continually or intermittently to maintain the initialpressure. When the amount of the monomers reaches a predetermined level,feeding is stopped. The monomers in the reaction container are purgedand the temperature is reduced to room temperature, whereby the reactionis completed. In this case, polymer latex can be continually taken outof the reaction container.

In particular, in the case of producing a thermoplastic elastomer as thefluoroelastomer, fluoropolymer fine particles may be synthesized at ahigh concentration as described above and then diluted for furtherpolymerization, as disclosed in WO 00/01741. This method can lead to amore rapid final polymerization rate than typical polymerization.

The polymerization for the fluoroelastomer may be performed underconditions appropriately selected in accordance with the physicalproperties of the target polymer and control of the polymerization rate,and is performed at a polymerization temperature of usually −20° C. to200° C., preferably 5° C. to 150° C., and a polymerization pressure ofusually 0.5 to 10 MPaG, preferably 1 to 7 MPaG. The polymerizationmedium preferably has a pH usually maintained at 2.5 to 13 using a pHadjuster to be described later by a known method, for example.

Examples of the monomer used in the polymerization for thefluoroelastomer include vinylidene fluoride, as well asfluorine-containing ethylenically unsaturated monomers that containfluorine atoms at least as much as the carbon atoms therein and that arecopolymerizable with vinylidene fluoride. Examples of thefluorine-containing ethylenically unsaturated monomers includetrifluoropropene, pentafluoropropene, hexafluorobutene, andoctafluorobutene. Hexafluoropropene is particularly preferred because ofthe properties of the elastomer obtained when hexafluoropropene blocksthe crystal growth of the polymer. Examples of the fluorine-containingethylenically unsaturated monomers also include trifluoroethylene, TFE,and CTFE. Alternatively, one or two or more fluorine-containing monomerscontaining a chlorine and/or bromine substituent(s) may also be used.Perfluoro(alkyl vinyl ethers) such as perfluoro(methyl vinyl ether) mayalso be used. TFE and HFP are preferred to produce a fluoroelastomer.

The fluoroelastomer preferably has a monomer composition ratio (% bymass) of vinylidene fluoride:HFP:TFE=(20 to 70):(30 to 48):(0 to 32).The fluoroelastomer having this composition ratio exhibits goodelastomeric characteristics, chemical resistance, and thermal stability.

In the polymerization for the fluoroelastomer, the surfactant may beused within the use range of the production method of the invention, andis usually added in an amount of 0.0001 to 20% by mass, preferably 10%by mass or less, more preferably 2% by mass or less, relative to 100% bymass of the aqueous medium.

In the polymerization for the fluoroelastomer, the polymerizationinitiator used may be a known inorganic radical polymerizationinitiator. Examples of particularly useful inorganic radicalpolymerization initiators include conventionally known water-solubleinorganic peroxides, such as a persulfates, superphosphates, perborates,percarbonates, and permanganates of sodium, potassium, or ammonium. Theradical polymerization initiator may be further activated with areducing agent such as a sulfite, a bisulfite, a metabisulfite, ahyposulfite, a thiosulfate, a phosphite, or a hypophosphite of sodium,potassium, or ammonium or an easily oxidizable metal compound such as aniron(II) salt, a copper(I) salt, or a silver salt. A preferred inorganicradical polymerization initiator is ammonium persulfate. More preferredis combination use of ammonium persulfate and sodium bisulfite in aredox system.

The polymerization initiator is added at a concentration appropriatelyselected in accordance with the molecular weight of the targetfluoropolymer and the polymerization reaction rate. The concentration isset to 0.0001 to 10% by mass, preferably 0.01 to 5% by mass, relative to100% by mass in total of all monomers.

In the polymerization for the fluoroelastomer, a known chain transferagent may be used. Examples thereof include hydrocarbons, esters,ethers, alcohols, ketones, chlorine compounds, and carbonates. Forthermoplastic elastomers, any of hydrocarbons, esters, ethers, alcohols,chlorine compounds, iodine compounds, and the like may be used.Preferred among these are acetone and isopropyl alcohol. In order toreduce a reaction rate drop in polymerization for a thermoplasticelastomer, isopentane, diethyl malonate, and ethyl acetate arepreferred. Diiodine compounds such as I(CF₂)₄I, I(CF₂)₆I, and ICH₂I arepreferred because they can iodize an end of the polymer and allow theresulting polymer to serve as a reactive polymer.

The chain transfer agent is usually used in an amount of 0.5×10⁻³ to5×10⁻³ mol %, preferably 1.0×10⁻³ to 3.5×10⁻³ mol %, relative to thewhole amount of the monomers fed.

In the polymerization for the fluoroelastomer, paraffin wax maypreferably be used as an emulsification stabilizer, for example. In thepolymerization for a thermoplastic elastomer, a phosphate, sodiumhydroxide, potassium hydroxide, or the like may preferably be used as apH adjuster.

At completion of the polymerization, the fluoroelastomer obtained by theproduction method of the invention has a solid content of 1.0 to 40% bymass, an average particle size of 0.03 to 1 μm, preferably 0.05 to 0.5μm, and a number average molecular weight of 1000 to 2000000.

The fluoroelastomer obtained by the production method of the inventionmay optionally be mixed with a dispersion stabilizer such as ahydrocarbon-based surfactant or be concentrated. Thereby, thefluoroelastomer is formed into a dispersion suitable for rubber molding.The dispersion is subjected to treatments such as pH control,solidification, and heating. The treatments are performed as follows.

The pH control is performed such that a mineral acid such as nitricacid, sulfuric acid, hydrochloric acid, or phosphoric acid and/or acarboxylic acid containing 5 or less carbon atoms and having pK=4.2 orlower is added to control the pH to 2 or lower.

The solidification is performed by adding an alkaline earth metal salt.Examples of the alkaline earth metal salt include a nitrate, chlorate,and acetate of calcium or magnesium.

The pH control and the solidification may be performed in any order, andthe pH control is preferably performed before.

These operations are followed by washing with water in an amount equalto the fluoroelastomer to remove a small amount of impurities such asbuffers and salts present in the fluoroelastomer and drying of thefluoroelastomer. The drying is usually performed at about 70° C. to 200°C. while the air is circulated in a drying furnace at high temperature.

The fluoroelastomer may be either a partially fluorinated elastomer or aperfluoroelastomer.

Examples of the partially fluorinated elastomer include vinylidenefluoride (VdF)-based fluoroelastomers, tetrafluoroethylene(TFE)/propylene (Pr)-based fluoroelastomers, tetrafluoroethylene(TFE)/propylene/vinylidene fluoride (VdF)-based fluoroelastomers,ethylene/hexafluoropropylene (HFP)-based fluoroelastomers,ethylene/hexafluoropropylene (HFP)/vinylidene fluoride (VdF)-basedfluoroelastomers, and ethylene/hexafluoropropylene(HFP)/tetrafluoroethylene (TFE)-based fluoroelastomers. The partiallyfluorinated elastomer preferably includes at least one selected from thegroup consisting of a vinylidene fluoride-based fluoroelastomer and atetrafluoroethylene/propylene-based fluoroelastomer.

The vinylidene fluoride-based fluoroelastomer is preferably a copolymercontaining 45 to 85 mol % of vinylidene fluoride and 55 to 15 mol % ofat least one different monomer copolymerizable with vinylidene fluoride.The vinylidene fluoride-based fluoroelastomer is more preferably acopolymer containing 50 to 80 mol % of vinylidene fluoride and 50 to 20mol % of at least one different monomer copolymerizable with vinylidenefluoride.

Examples of the at least one different monomer copolymerizable withvinylidene fluoride include monomers such as tetrafluoroethylene (TFE),hexafluoropropylene (HFP), fluoroalkyl vinyl ethers,chlorotrifluoroethylene (CTFE), trifluoroethylene, trifluoropropylene,pentafluoropropylene, trifluorobutene, tetrafluoroisobutene,hexafluoroisobutene, vinyl fluoride, a fluoromonomer represented by theformula (100): CH₂═CFRf¹⁰¹ (wherein Rf¹⁰¹ is a C1-C12 linear or branchedfluoroalkyl group), a fluoromonomer represented by the formula (170):CH₂═CH—(CF₂)_(n)—X¹⁷¹ (wherein X¹⁷¹ is H or F; and n is an integer of 3to 10), and a monomer giving a crosslinking site; and non-fluorinatedmonomers such as ethylene, propylene, and alkyl vinyl ethers. These maybe used alone or in any combination thereof. At least one selected fromthe group consisting of TFE, HFP, fluoroalkyl vinyl ethers, and CTFE ispreferably used. The fluoroalkyl vinyl ethers are preferablyfluoromonomers represented by the formula (110).

Specific examples of the vinylidene fluoride-based fluoroelastomersinclude VdF/HFP-based rubber, VdF/HFP/TFE-based rubber, VdF/CTFE-basedrubber, VdF/CTFE/TFE-based rubber, rubber based on VDF and afluoromonomer represented by the formula (100), rubber based on VDF, afluoromonomer represented by the formula (100), and TFE, rubber based onVDF and perfluoro(methyl vinyl ether) (PMVE), VDF/PMVE/TFE-based rubber,and VDF/PMVE/TFE/HFP-based rubber. The rubber based on VDF and afluoromonomer represented by the formula (100) is preferablyVDF/CH₂═CFCF₃-based rubber. The rubber based on VDF, a fluoromonomerrepresented by the formula (100), and TFE is preferablyVDF/TFE/CH₂═CFCF₃-based rubber.

The VDF/CH₂═CFCF₃-based rubber is preferably a copolymer containing 40to 99.5 mol % of VDF and 0.5 to 60 mol % of CH₂═CFCF₃, more preferably acopolymer containing 50 to 85 mol % of VDF and 20 to 50 mol % ofCH₂═CFCF₃.

The tetrafluoroethylene/propylene-based fluoroelastomer is preferably acopolymer containing 45 to 70 mol % of tetrafluoroethylene, 55 to 30 mol% of propylene, and 0 to 5 mol % of a fluoromonomer giving acrosslinking site.

The fluoroelastomer may be a perfluoroelastomer. The perfluoroelastomerpreferably includes at least one selected from the group consisting ofperfluoroelastomers containing TFE, such as a copolymer containing TFEand a fluoromonomer represented by the formula (110), (130), or (140)and a copolymer containing TFE, a fluoromonomer represented by theformula (110), (130), or (140), and a monomer giving a crosslinkingsite.

For the TFE/PMVE copolymer, the composition ratio thereof is preferably(45 to 90)/(10 to 55) (mol %), more preferably (55 to 80)/(20 to 45),still more preferably (55 to 70)/(30 to 45).

For the copolymer of TFE, PMVE, and a monomer giving a crosslinkingsite, the composition ratio thereof is preferably (45 to 89.9)/(10 to54.9)/(0.01 to 4) (mol %), more preferably (55 to 77.9)/(20 to49.9)/(0.1 to 3.5), still more preferably (55 to 69.8)/(30 to 44.8)/(0.2to 3).

For the copolymer of TFE and a C4-C12 fluoromonomer represented by theformula (110), (130), or (140), the composition ratio thereof ispreferably (50 to 90)/(10 to 50) (mol %), more preferably (60 to 88)/(12to 40), still more preferably (65 to 85)/(15 to 35).

For the copolymer of TFE, a C4-C12 fluoromonomer represented by theformula (110), (130), or (140), and a monomer giving a crosslinkingsite, the composition ratio thereof is preferably (50 to 89.9)/(10 to49.9)/(0.01 to 4) (mol %), more preferably (60 to 87.9)/(12 to39.9)/(0.1 to 3.5), still more preferably (65 to 84.8)/(15 to 34.8)/(0.2to 3).

Each of the above copolymers having a composition ratio outside theabove corresponding range tends to lose the properties as a rubberelastic article and to have properties close to those of a resin.

The perfluoroelastomer is preferably at least one selected from thegroup consisting of copolymers of TFE, a fluoromonomer represented bythe formula (140), and a fluoromonomer giving a crosslinking site,copolymers of TFE and a perfluorovinyl ether represented by the formula(140), copolymers of TFE and a fluoromonomer represented by the formula(110), and copolymers of TFE, a fluoromonomer represented by the formula(110), and a monomer giving a crosslinking site.

The perfluoroelastomer may also be any of the perfluoroelastomersdisclosed in documents such as WO 97/24381, JP S61-57324 B, JP H04-81608B, and JP H05-13961 B.

In order to achieve an excellent compression set at high temperature,the fluoroelastomer preferably has a glass transition temperature of−70° C. or higher, more preferably −60° C. or higher, still morepreferably −50° C. or higher. In order to achieve good cold resistance,the glass transition temperature is preferably 5° C. or lower, morepreferably 0° C. or lower, still more preferably −3° C. or lower.

The glass transition temperature can be determined as follows.Specifically, using a differential scanning calorimeter (DSC822e,available from Mettler-Toledo International Inc.), 10 mg of a sample isheated at a rate of 10° C./min to give a DSC curve, and the temperatureis read at the intermediate point of two intersections between each ofthe extension lines of the base lines before and after the secondarytransition of the DSC curve and the tangent line at the inflection pointof the DSC curve.

In order to achieve good heat resistance, the fluoroelastomer preferablyhas a Mooney viscosity ML(1+20) of 30 or higher, more preferably 40 orhigher, still more preferably 50 or higher, at 170° C. In order toachieve good processability, this Mooney viscosity is preferably 150 orlower, more preferably 120 or lower, still more preferably 110 or lower.

In order to achieve good heat resistance, the fluoroelastomer preferablyhas a Mooney viscosity ML(1+20) of 30 or higher, more preferably 40 orhigher, still more preferably 50 or higher, at 140° C. In order toachieve good processability, this Mooney viscosity is preferably 180 orlower, more preferably 150 or lower, still more preferably 110 or lower.

In order to achieve good heat resistance, the fluoroelastomer preferablyhas a Mooney viscosity ML(1+10) of 10 or higher, more preferably 20 orhigher, still more preferably 30 or higher, at 100° C. In order toachieve good processability, this Mooney viscosity is preferably 120 orlower, more preferably 100 or lower, still more preferably 80 or lower.

The Mooney viscosity can be determined using a Mooney viscometer MV2000Eavailable from Alpha Technologies Inc. at 170° C., 140° C., or 100° C.in conformity with JIS K 6300.

The fluoroelastomer obtained by the production method of the inventionmay be in any form as long as it is obtainable by the polymerization.The fluoroelastomer may be an aqueous dispersion as it is obtained bythe polymerization, or may be used in the form of a gum or a crumbobtained by conventional agglomeration, drying, and any other treatmenton the aqueous dispersion as it is obtained by the polymerization. Anemulsifier used in the production method of the invention can improvethe stability of an emulsion, and is more preferably used in apolymerization method in which substances insoluble in water such as aninitiator, including an organic peroxide, and a chain transfer agent,including an iodine or bromine compound, are added during thepolymerization as described above.

The gum is a small particulate mass of the fluoroelastomer. The crumb isan unshaped mass of the fluoroelastomer resulting from fusion ofparticles that cannot maintain the form of small particles as gum atroom temperature.

The fluoroelastomer may be mixed with any additive such as a curingagent and filler to be processed into a fluoroelastomer composition.

Examples of the curing agent include polyols, polyamines, organicperoxides, organotins, bis(aminophenol)tetraamine, andbis(thioaminophenol).

The fluoroelastomer composition contains the fluoroelastomer, and thusis substantially free from an emulsifier and is excellent in that it iseasily crosslinked during molding.

The fluoroelastomer may be molded to form a fluoroelastomer moldedarticle. The molding may be performed by any method such as a knownmethod using the aforementioned curing agent.

The fluoroelastomer molded article is suitable for seals, gaskets,electric wire coatings, hoses, tubes, laminates, and accessories,particularly parts for semiconductor manufacturing devices andautomobile parts.

The polymerization can usually provide an aqueous dispersion containingthe fluoropolymer. The fluoropolymer is usually at a concentration of 8to 50% by mass of the aqueous dispersion obtained by the polymerization.In the aqueous dispersion, the lower limit of the concentration of thefluoropolymer is preferably 10% by mass, more preferably 15% by mass,while the upper limit thereof is preferably 40% by mass, more preferably35% by mass.

The aqueous dispersion obtained by the polymerization may beconcentrated or subjected to dispersion stabilization treatment into adispersion, or may be precipitated or agglomerated, collected, and driedinto powder or other solid (e.g., pellets). The production method of theinvention is less likely to allow the surfactant to remain in the powderor pellets.

The surfactant is also suitably used as a dispersant for dispersing thefluoropolymer obtained by the polymerization in an aqueous medium.

The polymerization usually provides an aqueous dispersion containingparticles of the fluoropolymer, the surfactant, and the aqueous medium.The aqueous dispersion contains particles of the fluoropolymer in anaqueous medium in the presence of the surfactant.

The surfactant is preferably present in an amount of 0.0001 to 9.5 partsby weight relative to 100 parts by weight of the aqueous dispersion.Less than 0.0001 parts by weight of the surfactant may cause poordispersion stability. More than 9.5 parts by weight of the surfactantmay fail to give a dispersing effect corresponding to the amountthereof, and thus is impractical. The lower limit of the amount of thesurfactant is more preferably 0.001 parts by weight, while the upperlimit thereof is more preferably 2 parts by weight.

The aqueous dispersion may be any of an aqueous dispersion obtained bythe polymerization, a dispersion obtained by concentrating this aqueousdispersion or subjecting the aqueous dispersion to dispersionstabilization treatment, and an aqueous dispersion obtained bydispersing powder of the fluoropolymer into an aqueous medium in thepresence of the surfactant.

The aqueous dispersion may also be produced as a purified aqueousdispersion by a method including bringing the aqueous dispersionobtained by the polymerization into contact with an anion exchange resinor a mixed bed containing an anion exchange resin and a cation exchangeresin in the presence of a nonionic surfactant, and concentrating theaqueous dispersion obtained by this step such that the solid content is30 to 70% by mass relative to 100% by mass of the aqueous dispersion.The nonionic surfactant may be, but is not limited to, any of those tobe described later. The anion exchange resin may be, but is not limitedto, a known one. The contact with the anion exchange resin may beachieved by a known method.

Examples of the anion exchange resin include known ones such as astrongly basic anion exchange resin containing as a functional group a—N⁺X⁻(CH₃)₃ group (wherein X is Cl or OH) and a strongly basic anionexchange resin containing a —N⁺X⁻(CH₃)₃(C2H₄OH) group (wherein X isdefined as described above).

Examples of the cation exchange resin include, but are not limited to,known ones such as a strongly acidic cation exchange resin containing asa functional group a —SO₃— group and a weakly acidic cation exchangeresin containing as a functional group a —COO— group. In order toachieve good removal efficiency, a strongly acidic cation exchange resinis preferred, a H⁺ form strongly acidic cation exchange resin is morepreferred.

The “mixed bed containing a cation exchange resin and an anion exchangeresin” encompasses, but is not limited to, those in which the resins arefilled into a single column, those in which the resins are filled intodifferent columns, and those in which the resins are dispersed in acoarse fluorine-containing polymer aqueous dispersion.

The concentration may be performed by a known method, such as phaseseparation, electroconcentration, or ultrafiltration. The concentrationenables the fluoropolymer concentration to be 30 to 70% by mass inaccordance with the use thereof. The concentration may impair thestability of the dispersion. In such a case, a dispersion stabilizer maybe further added. The dispersion stabilizer added may be theaforementioned surfactant or any variety of surfactants. Examples of avariety of dispersion stabilizers include, but are not limited to,nonionic surfactants such as polyoxyalkyl ethers, particularlypolyoxyethylene alkyl phenyl ethers (e.g., Triton X-100 (trade name)available from Rohm and Haas Co.), polyoxyethylene isotridecyl ethers(e.g., Noigen TDS80C (trade name) available from DKS Co., Ltd., LeocolTD90D (trade name) available from Lion Corp., and Genapol X080 (tradename) available from Clariant), and polyoxyethylene ethers.

The whole amount of the dispersion stabilizer corresponds to aconcentration of 0.5 to 20% by mass relative to the solid content of thedispersion. Less than 0.5% by mass of the dispersion stabilizer maycause poor dispersion stability. More than 20% by mass thereof may failto give a dispersing effect corresponding to the amount thereof, andthus is impractical. The lower limit of the amount of the dispersionstabilizer is more preferably 2% by mass, while the upper limit thereofis more preferably 12% by mass.

The surfactant may be removed by the concentration operation.

The aqueous dispersion obtained by the polymerization may also besubjected to a dispersion stabilization treatment without concentrationfor some applications. This can provide an aqueous dispersion having along pot life. Examples of the dispersion stabilizer used include thesame as those described above.

Examples of the applications of the aqueous dispersion include, but arenot limited to, those in which the aqueous dispersion is directly used,such as coating achieved by applying the aqueous dispersion to asubstrate, drying the dispersion, and optionally firing the workpiece;impregnation achieved by impregnating the aqueous dispersion into aporous support such as nonwoven fabric or a resin molded article, dryingthe dispersion, and preferably firing the workpiece; and castingachieved by applying the aqueous dispersion to a substrate such asglass, drying the dispersion, optionally immersing the workpiece intowater, and removing the substrate to provide a film. Examples of suchapplications include aqueous dispersion-type coating materials, bindersfor electrodes, and water repellents for electrodes.

The aqueous dispersion may be mixed with any of compounding agents suchas known pigments, thickening agents, viscosity controlling agents,leveling agents, dispersion stabilizers (stabilizing agents) forimproving the mechanical stability or storage stability, pH adjusterssuch as ammonia water, antifoam, preservatives, antibacterial agents,fillers, antifreezing agents, film-forming aids, film-forming agents,and organic solvents, or may be combined with another polymer compound.Thereby, the aqueous dispersion may be used in the form of an aqueouscoating material for coating.

In order to control the viscosity of the aqueous dispersion or toimprove the miscibility with a pigment or filler, the aqueous dispersionmay preferably contain an anionic surfactant. The anionic surfactant isadded appropriately to the extent that causes no problems from theeconomic and environmental viewpoints.

Examples of the anionic surfactant include non-fluorinated anionicsurfactants and fluorinated anionic surfactants. Preferred arefluorine-free, non-fluorinated anionic surfactants, i.e., hydrocarbonanion surfactants.

In order to control the viscosity, any known anionic surfactants may beused, such as anionic surfactants disclosed in WO 2013/146950 and WO2013/146947. Examples thereof include those containing a C6-C40,preferably C8-C20, more preferably C9-C13 saturated or unsaturatedaliphatic chain. The saturated or unsaturated aliphatic chain may beeither linear or branched, or may have a cyclic structure. Thehydrocarbon may have aromaticity, or may contain an aromatic group. Thehydrocarbon may contain a hetero atom such as oxygen, nitrogen, orsulfur.

Examples of the anionic surfactants include alkyl sulfonates, alkylsulfates, and alkyl aryl sulfates, and salts thereof; aliphatic(carboxylic) acids and salts thereof; and phosphoric acid alkyl estersand phosphoric acid alkyl aryl esters, and salts thereof. Preferredamong these are alkyl sulfonates, alkyl sulfates, and aliphaticcarboxylic acids, and salts thereof. Preferred examples of the alkylsulfates and salts thereof include ammonium lauryl sulfate and sodiumlauryl sulfate.

Preferred examples of the aliphatic carboxylic acids and salts thereofinclude succinic acid, decanoic acid, undecanoic acid, undecenoic acid,lauric acid, hydrododecanoic acid, and salts thereof.

The anionic surfactant is preferably added in an amount of 10 to 5000ppm of the solid mass of the fluoropolymer, although the amount is inaccordance with the types of the anion surfactant and other compoundingagents.

The lower limit of the amount of the anionic surfactant is morepreferably 50 ppm or more, still more preferably 100 ppm or more. Toosmall an amount of the anionic surfactant may have a poor viscositycontrolling effect.

The upper limit of the amount of the anionic surfactant is morepreferably 3000 ppm or less, still more preferably 2000 ppm or less. Toolarge an amount of the anionic surfactant may cause poor mechanicalstability and storage stability of the aqueous dispersion.

In order to control the viscosity of the aqueous dispersion, componentsother than the anionic surfactants, such as methyl cellulose, aluminasol, polyvinyl alcohol, and carboxylated vinyl polymers may also beadded.

The aqueous dispersion may optionally contain a different polymercompound to the extent that does not impair the characteristics of theaqueous dispersion.

Examples of the different polymer compound include, but are not limitedto, polyethylene oxide (dispersion stabilizers), polyethylene glycol(dispersion stabilizers), phenol resin, urea resin, epoxy resin,melamine resin, polyester resin, polyether resin, silicone acrylicresin, silicone resin, silicone polyester resin, and polyurethane resin.

The surfactant, decomposition products and by-products of thesurfactant, and residual monomers may be collected from wastewatergenerated in the agglomeration or the washing and/or off gas generatedin the drying and then may be purified, whereby the surfactant, thedecomposition products and by-products of the surfactant, and theresidual monomers may be reused. The collection and the purification maybe performed by known methods, although not limited thereto. Forexample, they may be performed by the methods disclosed in JP2011-520020 T.

The collection of the surfactant, the decomposition products andby-products of the surfactant, and the residual monomers from wastewatergenerated in the agglomeration, wastewater generated in the washing, andoff gas generated in the drying and the purification thereof may beperformed by any known methods, although not limited thereto, such asthe methods disclosed in US 2007/15937 A, US 2007/25902 A, and US2007/27251 A. Specific examples of the methods are as follows.

An example of the method of collecting the surfactant, the decompositionproducts and by-products of the surfactant, and the residual monomersfrom wastewater is a method in which the wastewater is brought intocontact with adsorption particles of ion exchange resin, activatedcarbon, silica gel, clay, zeolite, or the like, so that the particlesare allowed to adsorb the surfactant and the others, and then thewastewater and the adsorption particles are separated. Incinerating theadsorption particles that adsorb the surfactant and the others canprevent emission of the surfactant and the others into the environment.

Alternatively, the surfactant and the others may also be collected bydesorbing and eluting the surfactant and the others by a known methodfrom the ion exchange resin particles having adsorbed the surfactant andthe others. For example, in the case of using anion exchange resinparticles as the ion exchange resin particles, the surfactant and theothers can be eluted by bringing a mineral acid into contact with ananion exchange resin. When the resulting eluate is mixed with awater-soluble organic solvent, the mixture is usually separated into twophases and the lower layer contains the surfactant and the others.Collecting and neutralizing the lower layer enables collection of thesurfactant and the others. Examples of the water-soluble organic solventinclude polar solvents such as alcohols, ketones, and ethers.

Other methods of collecting the surfactant and the others from ionexchange resin particles include a method of using an ammonium salt anda water-soluble organic solvent and a method of using an alcohol and, ifnecessary, an acid. In the latter method, ester derivatives of thesurfactant and the others are generated. They can easily be separatedfrom the alcohol by distillation.

If the wastewater contains fluoropolymer particles and other solidcomponents, they are preferably removed before the wastewater and theadsorption particles are brought into contact with each other. Examplesof methods of removing the fluoropolymer particles and other solidcomponents include a method of adding an aluminum salt, for example, todeposit the target components, and then separating the wastewater andthe deposits, and electrocoagulation. The components may also be removedby a mechanical method, such as crossflow filtration, depth filtration,or precoat filtration.

In order to achieve good productivity, the wastewater preferablycontains the fluoropolymer in a non-agglomerated form in a lowconcentration, more preferably less than 0.4% by mass, particularlypreferably less than 0.3% by mass.

An example of the method of collecting the surfactant and the othersfrom the off gas is a method in which a scrubber is brought into contactwith deionized water, an alkaline aqueous solution, an organic solventsuch as a glycol ether solvent, or the like to provide a scrubbersolution containing the surfactant and the others. The use of aconcentrated alkaline solution as an alkaline aqueous solution enablescollection of the scrubber solution with the surfactant and the othersbeing phase-separated. This results in easy collection and reuse of thesurfactant and the others. Examples of the alkali compound includealkali metal hydroxides and quaternary ammonium salts.

The scrubber solution containing the surfactant and the others may beconcentrated using a reverse osmosis membrane, for example. Theconcentrated scrubber solution usually contains fluoride ions. Still,the fluoride ions may be removed by adding alumina after theconcentration so that the surfactant and the others can easily bereused. Alternatively, the scrubber solution may be brought into contactwith adsorption particles so that the adsorption particles can adsorbthe surfactant and the others, and thereby the surfactant and the othersmay be collected by the aforementioned method.

The surfactant and the others collected by any of the above methods maybe reused in production of a fluoropolymer.

The invention also relates to a surfactant for polymerization thatincludes at least one selected from the group consisting of:

a surfactant (a) represented by the following formula (a):

(wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group;

R^(1a), R^(2a), and R^(3a) contain five or more carbon atoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a) s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring); and

a surfactant (b) represented by the following formula (b):

(wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C10 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom,NR^(5b) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to A^(b) in the formula).

The surfactant for polymerization can suitably be used as the surfactantused in the production method of the invention. A preferred structure ofthe surfactant for polymerization is the same as that of the surfactantused in the production method of the invention.

The invention also relates to use of a surfactant for production of afluoropolymer by polymerization of a fluoromonomer in an aqueous medium,the surfactant including at least one selected from the group consistingof:

a surfactant (a) represented by the following formula (a):

(wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group; R^(1a), R^(2a), and R^(3a) contain five or more carbonatoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a)s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring); and

a surfactant (b) represented by the following formula (b):

(wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C10 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom,NR^(5b) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to A^(b) in the formula).

The aqueous medium, the fluoromonomer, and the fluoropolymer arepreferably the same as those to be used in the production method of theinvention. A preferred structure of the surfactant is the same as thatof the surfactant used in the production method of the invention.

The invention also relates to a composition containing a fluoropolymerand at least one surfactant selected from the group consisting of:

a surfactant (a) represented by the following formula (a):

(wherein

R^(1a) is a linear or branched alkyl group containing one or more carbonatoms or a cyclic alkyl group containing three or more carbon atoms,with a hydrogen atom that binds to a carbon atom therein beingoptionally replaced by a hydroxy group or a monovalent organic groupthat contains an ester bond, optionally contains a carbonyl group whencontaining two or more carbon atoms, and optionally contains amonovalent or divalent heterocycle or optionally forms a ring whencontaining three or more carbon atoms;

R^(2a) and R^(3a) are each individually a single bond or a divalentlinking group;

R^(1a), R^(2a), and R^(3a) contain five or more carbon atoms in total;

A^(a) is —COOX^(a) or —SO₃X^(a), wherein X^(a) is H, a metal atom,NR^(4a) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(4a) s are each H or an organic groupand are the same as or different from each other; and

any two of R^(1a), R^(2a), and R^(3a) optionally bind to each other toform a ring); and

a surfactant (b) represented by the following formula (b):

(wherein

R^(1b) is a linear or branched alkyl group containing one or more carbonatoms and optionally containing a substituent or a cyclic alkyl groupcontaining three or more carbon atoms and optionally containing asubstituent, and optionally contains a monovalent or divalentheterocycle or optionally forms a ring when containing three or morecarbon atoms;

R^(2b) and R^(4b) are each individually H or a substituent;

R^(3b) is a C1-C10 alkylene group optionally containing a substituent;

n is an integer of 1 or greater;

p and q are each individually an integer of 0 or greater;

A^(b) is —SO₃X^(b) or —COOX^(b), wherein X^(b) is H, a metal atom,NR^(5b) ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent, where R^(5b)s are each H or an organic groupand are the same as or different from each other;

any two of R^(1b), R^(2b), R^(3b), and R^(4b) optionally bind to eachother to form a ring; and

L is a single bond, —CO₂—B—*, —OCO—B—*, —CONR^(6b)—B—*, —NR^(6b)CO—B—*,or —CO— other than the carbonyl groups in —CO₂—B—, —OCO—B—,—CONR^(6b)—B—, and —NR^(6b)CO—B—, where B is a single bond or a C1-C10alkylene group optionally containing a substituent, R^(6b) is H or aC1-C4 alkyl group optionally containing a substituent, and * indicatesthe bond to A^(b) in the formula). The composition of the invention is acomposition containing a fluoropolymer and the surfactant (a), acomposition containing a fluoropolymer and the surfactant (b), or acomposition containing a fluoropolymer, the surfactant (a), and thesurfactant (b).

The fluoropolymer is preferably the same as that to be used in theproduction method of the invention, more preferably a fluororesin, stillmore preferably a fluororesin having a fluorine substitution percentageof 50% or higher, further more preferably a fluororesin having afluorine substitution percentage of higher than 50%, still further morepreferably a fluororesin having a fluorine substitution percentage of55% or higher, much more preferably a fluororesin having a fluorinesubstitution percentage of 60% or higher, still much more preferably afluororesin having a fluorine substitution percentage of 75% or higher,particularly preferably a fluororesin having a fluorine substitutionpercentage of 80% or higher, most preferably a fluororesin having afluorine substitution percentage of 90 to 100%, i.e., a perfluororesin.

The perfluororesin is more preferably a fluororesin having a fluorinesubstitution percentage of 95 to 100%, still more preferably PTFE, FEP,or PFA, particularly preferably PTFE.

A preferred structure of the surfactant is the same as that of thesurfactant used in the production method of the invention.

An embodiment of the invention may be in the form of an aqueousdispersion, powder, or pellets. The aqueous dispersion may be adispersion immediately after the polymerization, or may be one obtainedby processing the dispersion immediately after the polymerization. Forexample, the aqueous dispersion may be mixed with a nonionic surfactantfor improved mechanical stability and storage stability. The nonionicsurfactant, when added, is preferably in an amount of 0.5 to 25% by massrelative to the fluoropolymer. The lower limit thereof is morepreferably 1% by mass, still more preferably 3% by mass, while the upperlimit thereof is more preferably 20% by mass, still more preferably 15%by mass, further more preferably 10% by mass.

The aqueous dispersion is a dispersion system in which an aqueous mediumserves as a dispersion medium and the fluoropolymer serves as adispersoid. The aqueous medium may be any liquid containing water, andmay contain, in addition to water, an organic solvent such as analcohol, an ether, a ketone, or paraffin wax.

The lower limit of the amount of the surfactant in the composition ispreferably 1 ppb, more preferably 10 ppb, still more preferably 100 ppb,further more preferably 1 ppm, particularly preferably 10 ppm, mostpreferably 50 ppm, relative to the fluoropolymer. The upper limitthereof is preferably 100000 ppm, more preferably 50000 ppm, still morepreferably 10000 ppm, further more preferably 5000 ppm, relative to thefluoropolymer.

The invention also relates to a composition containing a fluoropolymerand substantially free from a compound represented by the followingformula (3).

The formula (3) is (H—(CF₂)₈—SO₃)_(q)M²,

wherein, M² is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and q is1 or 2.

The fluoropolymer is preferably the same as that to be used in theproduction method of the invention, more preferably a fluororesin, stillmore preferably a fluororesin having a fluorine substitution percentageof 50% or higher, further more preferably a fluororesin having afluorine substitution percentage of higher than 50%, still further morepreferably a fluororesin having a fluorine substitution percentage of55% or higher, much more preferably a fluororesin having a fluorinesubstitution percentage of 60% or higher, still much more preferably afluororesin having a fluorine substitution percentage of 75% or higher,particularly preferably a fluororesin having a fluorine substitutionpercentage of 80% or higher, most preferably a fluororesin having afluorine substitution percentage of 90 to 100%, i.e., a perfluororesin.

The perfluororesin is more preferably a fluororesin having a fluorinesubstitution percentage of 95 to 100%, still more preferably PTFE, FEP,or PFA, particularly preferably PTFE.

The composition of the invention is substantially free from a compoundrepresented by the formula (3).

The phrase “substantially free from a compound represented by theformula (3)” means that, for example, the compound represented by theformula (3) is in an amount of 1000 ppb or less relative to thefluoropolymer. The amount of the compound represented by the formula (3)is preferably 500 ppb or less, more preferably 100 ppb or less, stillmore preferably 25 ppb or less, particularly preferably 15 ppb or less,further more preferably 10 ppb or less, relative to the fluoropolymer.The lower limit thereof may be, but is not limited to, 0 ppb or 1 ppb.

In the case where the composition of the invention is in the form of anaqueous dispersion, the quantification limit for the amount of thecompound represented by the formula (3) measured by the method to bedescribed later is about 10 to 100 ppb. Still, the quantification limitcan be reduced by performing concentration. Concentration may berepeated multiple times.

In an embodiment of the invention, the composition may be in the form ofan aqueous dispersion or may be in the form of powder. The aqueousdispersion may be a dispersion immediately after the polymerization, ormay be one obtained by processing the dispersion immediately after thepolymerization. For example, the aqueous dispersion may be mixed with anonionic surfactant for improved mechanical stability and storagestability.

The aqueous dispersion is a dispersion system in which an aqueous mediumserves as a dispersion medium and the fluoropolymer serves as adispersoid. The aqueous medium may be any liquid containing water, andmay contain, in addition to water, an organic solvent such as analcohol, an ether, a ketone, or paraffin wax.

In production of the fluoropolymer using a hydrocarbon-based surfactant,the resulting aqueous dispersion may contain a compound represented bythe following formula (4), (4′), (5), or (5′). In an embodiment of theinvention, the composition contains such a compound in an amount withinthe following range.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (4) in an amount of 100 ppb or morerelative to the fluoropolymer. The upper limit of the amount of thecompound represented by the formula (4) may be, but is not limited to,1000000 ppb, or may be 100000 ppb, or may be 10000 ppb, or may be 5000ppb. The lower limit of the amount of the compound represented by theformula (4) may be 500 ppb, or may be 1000 ppb.

The formula (4) is (H—(CF₂)₇—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In another embodiment of the invention, the composition contains acompound represented by the following formula (4′) in an amount of 100ppb or more relative to the fluoropolymer. The upper limit of the amountof the compound represented by the formula (4′) may be, but is notlimited to, 1000000 ppb, or may be 100000 ppb, or may be 10000 ppb, ormay be 5000 ppb. The lower limit of the amount of the compoundrepresented by the formula (4′) may be 500 ppb, or may be 1000 ppb.

The formula (4′) is (H—(CF₂)₈—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In another embodiment of the invention, the composition contains acompound represented by the following formula (4) in an amount of 100ppb or more relative to the fluoropolymer and/or contains a compoundrepresented by the following formula (4′) in an amount of 100 ppb ormore relative to the fluoropolymer. The upper limit of the amount of thecompound represented by the formula (4) may be, but is not limited to,1000000 ppb, or may be 100000 ppb, or may be 10000 ppb, or may be 5000ppb. The lower limit of the amount of the compound represented by theformula (4) may be 500 ppb, or may be 1000 ppb. The upper limit of theamount of the compound represented by the formula (4′) may be, but isnot limited to, 1000000 ppb, or may be 100000 ppb, or may be 10000 ppb,or may be 5000 ppb. The lower limit of the amount of the compoundrepresented by the formula (4′) may be 500 ppb, or may be 1000 ppb.

The formula (4) is (H—(CF₂)₇—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

The formula (4′) is (H—(CF₂)₈—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (5) in an amount of 100 ppb or morerelative to the fluoropolymer. The upper limit of the amount of thecompound represented by the formula (5) may be, but is not limited to,1000000 ppb, or may be 100000 ppb, or may be 10000 ppb, or may be 5000ppb. The lower limit of the amount of the compound represented by theformula (5) may be 500 ppb, or may be 1000 ppb.

The formula (5) is (H—(CF₂)₁₃—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (5′) in an amount of 100 ppb ormore relative to the fluoropolymer. The upper limit of the amount of thecompound represented by the formula (5′) may be, but is not limited to,1000000 ppb, or may be 100000 ppb, or may be 10000 ppb, or may be 5000ppb. The lower limit of the amount of the compound represented by theformula (5′) may be 500 ppb, or may be 1000 ppb.

The formula (5′) is (H—(CF₂)₁₄—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In another embodiment of the invention, the composition contains acompound represented by the following formula (5) in an amount of 100ppb or more relative to the fluoropolymer and/or contains a compoundrepresented by the following formula (5′) in an amount of 100 ppb ormore relative to the fluoropolymer. The upper limit of the amount of thecompound represented by the formula (5) may be, but is not limited to,1000000 ppb, or may be 100000 ppb, or may be 10000 ppb, or may be 5000ppb. The lower limit of the amount of the compound represented by theformula (5) may be 500 ppb, or may be 1000 ppb. The upper limit of theamount of the compound represented by the formula (5′) may be, but isnot limited to, 1000000 ppb, or may be 100000 ppb, or may be 10000 ppb,or may be 5000 ppb. The lower limit of the amount of the compoundrepresented by the formula (5′) may be 500 ppb, or may be 1000 ppb.

The formula (5) is (H—(CF₂)₁₃—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

The formula (5′) is (H—(CF₂)₁₄—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In the case where the composition of the invention is in the form of anaqueous dispersion, the amount of the compound represented by theformula (4), (4′), (5), or (5′) may fall within the following range.

The aqueous dispersion may contain a nonionic surfactant for improvedstability. The nonionic surfactant used may be, but is not limited to, aconventionally known nonionic surfactant.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (4) in an amount of 1000 ppb orless relative to the fluoropolymer and contains 1% by mass or more of anonionic surfactant. The upper limit of the amount of the nonionicsurfactant is preferably 10% by mass, for example. The amount of thecompound represented by the formula (4) is more preferably 500 ppb orless, still more preferably 100 ppb or less, particularly preferably 25ppb or less, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit thereof may be, but is notlimited to, 1 ppb.

The formula (4) is (H—(CF₂)₇—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (4′) in an amount of 1000 ppb orless relative to the fluoropolymer and contains 1% by mass or more of anonionic surfactant. The upper limit of the amount of the nonionicsurfactant is preferably 10% by mass, for example. The amount of thecompound represented by the formula (4′) is more preferably 500 ppb orless, still more preferably 100 ppb or less, particularly preferably 25ppb or less, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit thereof may be, but is notlimited to, 1 ppb.

The formula (4′) is (H—(CF₂)₈—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains at least oneof a compound represented by the formula (4) or a compound representedby the formula (4′), with the compound represented by the formula (4)being in an amount of 1000 ppb or less relative to the fluoropolymer andwith the compound represented by the formula (4′) being in an amount of1000 ppb or less relative to the fluoropolymer, and 1% by mass or moreof a nonionic surfactant. The upper limit of the amount of the nonionicsurfactant is preferably 10% by mass, for example. The amount of thecompound represented by the formula (4) is more preferably 500 ppb orless, still more preferably 100 ppb or less, particularly preferably 25ppb or less, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit of the amount of the compoundrepresented by the formula (4) may be, but is not limited to, 0 ppb or 1ppb. The amount of the compound represented by the formula (4′) is morepreferably 500 ppb or less, still more preferably 100 ppb or less,particularly preferably 25 ppb or less, further more preferably 15 ppbor less, still further more preferably 10 ppb or less. The lower limitof the amount of the compound represented by the formula (4′) may be,but is not limited to, 0 ppb or 1 ppb.

The formula (4) is (H—(CF₂)₇—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

The formula (4′) is (H—(CF₂)₈—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (5) in an amount of 1000 ppb orless relative to the fluoropolymer and contains 1% by mass or more of anonionic surfactant. The upper limit of the amount of the nonionicsurfactant is preferably 10% by mass, for example. The amount of thecompound represented by the formula (5) is more preferably 500 ppb orless, still more preferably 100 ppb or less, particularly preferably 25ppb or less, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit thereof may be, but is notlimited to, 1 ppb.

The formula (5) is (H—(CF₂)₁₃—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (5′) in an amount of 1000 ppb orless relative to the fluoropolymer and contains 1% by mass or more of anonionic surfactant. The upper limit of the amount of the nonionicsurfactant is preferably 10% by mass, for example. The amount of thecompound represented by the formula (5′) is more preferably 500 ppb orless, still more preferably 100 ppb or less, particularly preferably 25ppb or less, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit thereof may be, but is notlimited to, 1 ppb.

The formula (5′) is (H—(CF₂)₁₄—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains at least oneof the compound represented by the formula (5) or the compoundrepresented by the formula (5′), with the compound represented by theformula (5) being in an amount of 1000 ppb or less relative to thefluoropolymer and with the compound represented by the formula (5′)being in an amount of 1000 ppb or less relative to the fluoropolymer,and 1% by mass or more of a nonionic surfactant. The upper limit of theamount of the nonionic surfactant is preferably 10% by mass, forexample. The amount of the compound represented by the formula (5) ismore preferably 500 ppb or less, still more preferably 100 ppb or less,particularly preferably 25 ppb or less, further more preferably 15 ppbor less, still further more preferably 10 ppb or less. The lower limitof the amount of the compound represented by the formula (5) may be, butis not limited to, 0 ppb or 1 ppb. The amount of the compoundrepresented by the formula (5′) is more preferably 500 ppb or less,still more preferably 100 ppb or less, particularly preferably 25 ppb orless, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit of the amount of the compoundrepresented by the formula (5′) may be, but is not limited to, 0 ppb or1 ppb.

The formula (5) is (H—(CF₂)₁₃—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

The formula (5′) is (H—(CF₂)₁₄—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In production of the fluoropolymer using a hydrocarbon-based surfactant,the resulting fluoropolymer powder may contain a compound represented bythe following formula (1), (2), (4), (4′), (5), or (5′). In the casewhere the composition of the invention is in the form of powder, theamount of the compound represented by the formula (1), (2), (4), (4′),(5), or (5′) may fall within the following range.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (4) in an amount of 1000 ppb orless relative to the fluoropolymer. The amount of the compoundrepresented by the formula (4) is more preferably 500 ppb or less, stillmore preferably 100 ppb or less, particularly preferably 25 ppb or less,further more preferably 15 ppb or less, still further more preferably 10ppb or less. The lower limit thereof may be, but is not limited to, 1ppb.

The formula (4) is (H—(CF₂)₇—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (4′) in an amount of 1000 ppb orless relative to the fluoropolymer. The amount of the compoundrepresented by the formula (4′) is more preferably 500 ppb or less,still more preferably 100 ppb or less, particularly preferably 25 ppb orless, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit thereof may be, but is notlimited to, 1 ppb.

The formula (4′) is (H—(CF₂)₈—COO)^(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains at least oneof the compound represented by the formula (4) or the compoundrepresented by the formula (4′), with the compound represented by theformula (4) being in an amount of 1000 ppb or less relative to thefluoropolymer and with the compound represented by the formula (4′)being in an amount of 1000 ppb or less relative to the fluoropolymer.The amount of the compound represented by the formula (4) is morepreferably 500 ppb or less, still more preferably 100 ppb or less,particularly preferably 25 ppb or less, further more preferably 15 ppbor less, still further more preferably 10 ppb or less. The lower limitof the amount of the compound represented by the formula (4) may be, butis not limited to, 0 ppb or 1 ppb. The amount of the compoundrepresented by the formula (4′) is more preferably 500 ppb or less,still more preferably 100 ppb or less, particularly preferably 25 ppb orless, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit of the amount of the compoundrepresented by the formula (4′) may be, but is not limited to, 0 ppb or1 ppb.

The formula (4) is (H—(CF₂)₇—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

The formula (4′) is (H—(CF₂)₈—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (5) in an amount of 1000 ppb orless relative to the fluoropolymer. The amount of the compoundrepresented by the formula (5) is more preferably 500 ppb or less, stillmore preferably 100 ppb or less, particularly preferably 25 ppb or less,further more preferably 15 ppb or less, still further more preferably 10ppb or less. The lower limit thereof may be, but is not limited to, 1ppb.

The formula (5) is (H—(CF₂)₁₃—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains a compoundrepresented by the following formula (5′) in an amount of 1000 ppb orless relative to the fluoropolymer. The amount of the compoundrepresented by the formula (5′) is more preferably 500 ppb or less,still more preferably 100 ppb or less, particularly preferably 25 ppb orless, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit thereof may be, but is notlimited to, 1 ppb.

The formula (5′) is (H—(CF₂)₁₄—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains at least oneof the compound represented by the formula (5) or the compoundrepresented by the formula (5′), with the compound represented by theformula (5) being in an amount of 1000 ppb or less relative to thefluoropolymer and with the compound represented by the formula (5′)being in an amount of 1000 ppb or less relative to the fluoropolymer.The amount of the compound represented by the formula (5) is morepreferably 500 ppb or less, still more preferably 100 ppb or less,particularly preferably 25 ppb or less, further more preferably 15 ppbor less, still further more preferably 10 ppb or less. The lower limitof the amount of the compound represented by the formula (5) may be, butis not limited to, 0 ppb or 1 ppb. The amount of the compoundrepresented by the formula (5′) is more preferably 500 ppb or less,still more preferably 100 ppb or less, particularly preferably 25 ppb orless, further more preferably 15 ppb or less, still further morepreferably 10 ppb or less. The lower limit of the amount of the compoundrepresented by the formula (5′) may be, but is not limited to, 0 ppb or1 ppb.

The formula (5) is (H—(CF₂)₁₃—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

The formula (5′) is (H—(CF₂)₁₄—COO)_(p)M¹,

wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2.

In an embodiment of the invention, the composition contains compoundsrepresented by the following formula (2) among which the amount of acompound with n=4 is 1000 ppb or less relative to the fluoropolymer, theamount of a compound with n=5 is 1000 ppb or less relative to thefluoropolymer, the amount of a compound with n=6 is 1000 ppb or lessrelative to the fluoropolymer, the amount of a compound with n=7 is 1000ppb or less relative to the fluoropolymer, the amount of a compound withn=8 is 1000 ppb or less relative to the fluoropolymer, the amount of acompound with n=9 is 1000 ppb or less relative to the fluoropolymer, theamount of a compound with n=10 is 1000 ppb or less relative to thefluoropolymer, the amount of a compound with n=11 is 1000 ppb or lessrelative to the fluoropolymer, the amount of a compound with n=12 is1000 ppb or less relative to the fluoropolymer, the amount of a compoundwith n=13 is 1000 ppb or less relative to the fluoropolymer, the amountof a compound with n=14 is 1000 ppb or less relative to thefluoropolymer, the amount of a compound with n=15 is 1000 ppb or lessrelative to the fluoropolymer, the amount of a compound with n=16 is1000 ppb or less relative to the fluoropolymer, the amount of a compoundwith n=17 is 1000 ppb or less relative to the fluoropolymer, the amountof a compound with n=18 is 1000 ppb or less relative to thefluoropolymer, the amount of a compound with n=19 is 1000 ppb or lessrelative to the fluoropolymer, the amount of a compound with n=20 is1000 ppb or less relative to the fluoropolymer.

The formula (2) is (H—(CF₂)_(n)—SO₃)_(q)M²,

wherein n is 4 to 20; M² is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and q is 1 or 2.

The amounts of compounds with n=4 to 20 are each more preferably 500 ppbor less, still more preferably 100 ppb or less, particularly preferably25 ppb or less, further more preferably 15 ppb or less, still furthermore preferably 10 ppb or less. The lower limit thereof may be, but isnot limited to, 0 ppb or 1 ppb. In the composition of the invention, theamount of any of the compounds represented by the formula (2) may be 0ppb.

In an embodiment of the invention, the composition contains compoundsrepresented by the following formula (1) among which the amount of acompound with m=3 is 1000 ppb or less relative to the fluoropolymer, theamount of a compound with m=4 is 1000 ppb or less relative to thefluoropolymer, the amount of a compound with m=5 is 1000 ppb or lessrelative to the fluoropolymer, the amount of a compound with m=6 is 1000ppb or less relative to the fluoropolymer, the amount of a compound withm=7 is 1000 ppb or less relative to the fluoropolymer, the amount of acompound with m=8 is 1000 ppb or less relative to the fluoropolymer, theamount of a compound with m=9 is 1000 ppb or less relative to thefluoropolymer, the amount of a compound with m=10 is 1000 ppb or lessrelative to the fluoropolymer, the amount of a compound with m=11 is1000 ppb or less relative to the fluoropolymer, the amount of a compoundwith m=12 is 1000 ppb or less relative to the fluoropolymer, the amountof a compound with m=13 is 1000 ppb or less relative to thefluoropolymer, the amount of a compound with m=14 is 1000 ppb or lessrelative to the fluoropolymer, the amount of a compound with m=15 is1000 ppb or less relative to the fluoropolymer, the amount of a compoundwith m=16 is 1000 ppb or less relative to the fluoropolymer, the amountof a compound with m=17 is 1000 ppb or less relative to thefluoropolymer, the amount of a compound with m=18 is 1000 ppb or lessrelative to the fluoropolymer, the amount of a compound with m=19 is1000 ppb or less relative to the fluoropolymer.

The formula (1) is (H—(CF₂)_(m)—COO)_(p)M¹,

wherein m is 3 to 19; M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or 2.

The amounts of compounds with m=3 to 19 are each more preferably 500 ppbor less, still more preferably 100 ppb or less, particularly preferably25 ppb or less, further more preferably 15 ppb or less, still furthermore preferably 10 ppb or less. The lower limit thereof may be, but isnot limited to, 0 ppb or 1 ppb. In an embodiment of the invention, thecomposition contains any of the compounds represented by the formula(1).

In the formula (1), (2), (3), (4), (4′), (5), or (5′), four R⁵s are thesame as or different from each other. Each R⁵ is preferably H or aC1-C10 organic group, more preferably H or a C1-C4 organic group.

In an embodiment of the invention, the composition may be in the form ofpowder. For the composition of the invention in the form of powder, thepowder preferably has an average particle size of 0.5 to 2000 m. Thelower limit of the average particle size is more preferably 1 m, morepreferably 1000 m, still more preferably 800 m.

The average particle size as used herein for low-molecular-weight PTFEis determined as follows. That is, the particle size distribution isdetermined using a laser diffraction particle size distribution analyzer(available from Japan Laser Corp.) at a pressure of 0.1 MPa and ameasurement time of 3 seconds without cascade impaction. The valuecorresponding to 50% of the cumulative volume in the resulting particlesize distribution is taken as the average particle size.

For high-molecular-weight PTFE, the average particle size is determinedin conformity with JIS K 6891.

The powder preferably has a tone L* of 50 or lower after the firing. Thetone L* is more preferably 45 or lower, still more preferably 40 orlower, particularly preferably 35 or lower, further more preferably 30or lower.

A sample for measurement of tone L* is prepared by molding 4.0 g of PTFEpowder into a discoidal PTFE molded article having an inner diameter of28.6 mm and a thickness of about 4 mm.

The tone L* of the powder is determined using a color difference meter(CIELAB color scale) in conformity with JIS Z 8781-4.

The firing is performed by heat treatment for 10 minutes in an electricfurnace heated up to 385° C.

The composition of the invention preferably exhibits a tone change ΔL*of 70% or higher before and after the fluorination treatment. The tonechange ΔL* is more preferably 80 or higher, still more preferably 90 orhigher.

The tone change ΔL* is defined by the following formula:

ΔL*(%)=(L* _(t) −L* _(i))/(L* _(std) −L* _(i))×100

L*_(i) is the initial tone, and is a measured value L* in the CIELABscale of PTFE before the fluorination treatment.

L*_(t) is the tone after the treatment, and is a measured value L* inthe CIELAB scale of PTFE after the fluorination treatment.

L*_(std)=87.3

The fluorination treatment is performed such that a gas mixture(fluorine/nitrogen (ratio by volume)=20/80) obtained by dilutingfluorine gas (F₂) as a fluorine radical source with nitrogen gas iscontinuously introduced into a reactor heated up to 150° C. or higherunder the atmospheric pressure at a flow rate of about 50 cc/min for 480minutes (8 hours).

In the composition of the invention, the amount of the compoundrepresented by the formula (1), (2), (3), (4), (4′), (5), or (5′) is avalue determined by liquid chromatography-mass spectrometry as in theexamples to be described later.

In the composition of the invention, the fluoropolymer is preferably oneobtained by polymerization using a hydrocarbon-based surfactant.

The composition of the invention may contain a hydrocarbon-basedsurfactant. Examples of the hydrocarbon-based surfactant include theaforementioned surfactants (a) and (b).

The composition may further contain any of conventionally knownadditives such as pigments and fillers in addition to the fluoropolymerand the hydrocarbon-based surfactant. The additives may be used to theextent that does not inhibit the effects of the invention.

The composition of the invention may be produced by the use of acarboxylic acid-based surfactant or a combination of a carboxylicacid-based surfactant and a specific polymerization initiator.

Examples of the carboxylic acid-based surfactant include surfactantswhich are among the above surfactants (a) and in which A^(a) is—COOX^(a) and surfactants which are among the above surfactants (b) andin which A^(b) is —COOX^(b).

Examples of the specific polymerization initiator include water-solubleradical polymerization initiators and redox polymerization initiators.

The water-soluble radical polymerization initiators may be knownwater-soluble peroxides, and examples thereof include ammonium salts,potassium salts, and sodium salts of persulfuric acid and percarbonicacid, t-butyl permaleate, and t-butyl hydroperoxide. The amount thereofmay be 0.1 to 20 times the amount of the peroxide.

For example, in the case of polymerization at a low temperature of 30°C. or lower, the polymerization initiator used is preferably a redoxinitiator that is a combination of an oxidizing agent and a reducingagent. Examples of the oxidizing agent include persulfates, organicperoxides, potassium permanganate, manganese triacetate, and ammoniumcerium nitrate. Examples of the reducing agent include bromic acidsalts, diimines, and oxalic acid. Examples of the persulfates includeammonium persulfate and potassium persulfate. In order to increase thedecomposition rate of the initiator, the combination of a redoxinitiator may preferably contain a copper salt or an iron salt. Anexample of the copper salt is copper(II) sulfate and an example of theiron salt is iron(II) sulfate.

Examples of the redox initiator include potassium permanganate/oxalicacid, manganese triacetate/oxalic acid, ammonium cerium nitrate/oxalicacid, and bromic acid salt. Preferred is potassium permanganate/oxalicacid. In the case of using a redox initiator, either an oxidizing agentor a reducing agent may be put into a polymerization tank in advance andthe other may be continually or intermittently added thereto to initiatethe polymerization. For example, in the case of potassiumpermanganate/oxalic acid, preferably, oxalic acid is put into apolymerization tank and potassium permanganate is continually addedthereto.

The invention also relates to a molded article containing thecomposition. The molded article is preferably a stretched article.Examples of the stretched article include, but are not limited to,yarns, tubes, tapes, and films (e.g., uniaxially stretched films andbiaxially stretched films).

The composition of the invention may also be produced by preparing afluoropolymer by the above method for producing a fluoropolymer, andthen treating the fluoropolymer by the following method, for example.

The fluoropolymer dispersion obtained using a hydrocarbon-basedsurfactant (e.g., the surfactant (a) or (b)) may contain a compoundrepresented by the formula (1), (2), (3), (4), (4′), (5), or (5′). Thecompound represented by the formula (1), (2), (3), (4), (4′), (5), or(5′) can be removed or reduced by the following method.

Examples of the method of removing or reducing the compound representedby the formula (3), (4), (4′), (5), or (5′) from the fluoropolymerdispersion include adsorption treatment and concentration treatment.

Examples of the adsorption treatment include methods using an adsorbentsuch as ion exchange resin (IER), activated carbon, or zeolite.Specifically, the compound represented by the formula (1), (2), (3),(4), (4′), (5), or (5′) contained in the fluoropolymer dispersion can beremoved or reduced by bringing the compound represented by the formula(1), (2), (3), (4), (4′), (5), or (5′) into contact with an adsorbent.

Examples of the concentration treatment include phase-separationconcentration, electrical concentration, filtration treatment using anultrafiltration membrane, filtration treatment using a reverse osmosismembrane (RO membrane), and nanofiltration treatment.

The adsorption treatment and the concentration treatment each may beperformed multiple times. For example, the adsorption treatment or theconcentration treatment may be performed twice, three times, four times,five times, six times, seven times, eight times, nine times, or tentimes. The adsorption treatment and the concentration treatment may beperformed in combination.

Agglomerating the fluoropolymer dispersion can lead to fluoropolymerpowder, for example.

Examples of a method of removing or reducing the compound represented bythe formula (1), (2), (3), (4), (4′), (5), or (5′) from thefluoropolymer powder include heat treatment, fluorination treatment, andwashing with water or an organic solvent.

Examples of the organic solvent include ethers, halogenatedhydrocarbons, aromatic hydrocarbons, pyridines, nitriles,nitrogen-containing polar organic compounds, dimethyl sulfoxide, andalcohols.

Examples of the ethers include diethyl ether, tetrahydrofuran, dioxane,and diethylene glycol diethyl ether.

Examples of the halogenated hydrocarbons include dichloromethane,dichloroethane, chloroform, chlorobenzene, and o-dichlorobenzene.

Examples of the aromatic hydrocarbons include benzene, toluene, andxylene.

Examples of the nitriles include acetonitrile, propionitrile,butyronitrile, isobutyronitrile, and benzonitrile.

Examples of the nitrogen-containing polar organic compounds includeN,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone,2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone.

Examples of the alcohols include methanol, ethanol, 1-propanol, andisopropanol.

The above organic solvents may be used in combination.

The heat treatment may be performed by any method, and may be performedby a conventionally known method. The heat treatment temperature ispreferably 150° C. to 310° C. The heat treatment temperature is morepreferably 170° C. or higher, still more preferably 180° C. or higher,further more preferably 200° C. or higher, still further more preferably210° C. or higher, particularly preferably 220° C. or higher, mostpreferably 230° C. or higher.

The heat treatment temperature is more preferably 300° C. or lower,still more preferably 290° C. or lower, further more preferably 280° C.or lower, still further more preferably 270° C. or lower.

The fluorination treatment may be performed by a conventionally knownmethod. An example thereof is a method of exposing the PTFE powder to afluorine radical source that generates fluorine radicals underfluorination conditions. Examples of the fluorine radical source includefluorine gas, as well as CoF₃, AgF₂, UF₆, OF₂, N₂F₂, CF₃OF, and halogenfluorides such as IF₅, ClF₃, and BrF₃.

A reaction with a fluorine radical source generates a large amount ofheat, so that the fluorine radical source may be diluted with an inertgas such as nitrogen.

The fluorine radical source level in a mixture of the fluorine radicalsource/inert gas may be 1 to 100% by volume. Still, operations with purefluorine are highly risky, and thus the level may be about 5 to about25% by volume. For fluorinated polymer resins which are very likely tosuffer heat-induced coloring, a mixture of the fluorine-radicalsource/inert gas may sufficiently be diluted so as to preventoverheating of the fluorinated polymer and the risk of fire associatedtherewith.

The above treatment may be performed multiple times on the fluoropolymerpowder. For example, the treatment may be performed twice, three times,four times, five times, six times, seven times, eight times, nine times,or ten times. The heat treatment and the fluorination treatment may beperformed in combination, and may be performed simultaneously.

The washing with water or an organic solvent may be performed by anymethod, and may be performed by a conventionally known method.

Examples of a method of removing or reducing the compound represented bythe formula (1), (2), (3), (4), (4′), (5), or (5′) from the moldedarticle include the above heat treatment and fluorination treatment.

The molded article may be produced by a method including, for example, astep (1a) of mixing the fluoropolymer powder and an extrusion aid, astep (1b) of paste extrusion molding the resulting mixture, a step (1c)of drying the extrudate obtained by the extrusion molding, and a step(1d) of firing the dried extrudate to provide a molded article. Theabove treatment may be performed after the step (1a) and before the step(1b), after the step (1b) and before the step (1c), or after the step(1d). In the case of performing the heat treatment as a removal stepafter the step (1d), the heat treatment temperature may be higher than310° C. In this case, the heat treatment is preferably performed at 500°C. or lower.

The treatment may be performed during the step (1b), the step (1c), orthe step (1d). The treatment may be performed multiple times. Forexample, the removal step may be performed twice, three times, fourtimes, five times, six times, seven times, eight times, nine times, orten times. The heat treatment and the fluorination treatment may beperformed in combination, and may be performed simultaneously.

The paste extrusion molding may be performed by a conventionally knownmethod, and the molding conditions may be selected in accordance withthe desired shape and size. The paste extrusion molding may be performedon the fluoropolymer powder mixed with a conventionally known additivesuch as a pigment or filler.

The molded article may be produced by a method including a step (2a) ofmixing fluoropolymer powder obtained by the use of a hydrocarbon-basedsurfactant and an extrusion aid, a step (2b) of extrusion-rolling theresulting mixture, a step (2c) of drying the extrudate obtained by theextrusion-rolling, a step (2d) of uniaxially stretching the driedextrudate, a step (2e) of biaxially stretching the uniaxially stretchedarticle, a step (2f) of firing the biaxially stretched article, and astep (2g) of stacking the fired article with another material. In thiscase, the treatment may be performed after the step (2a) and before thestep (2b), after the step (2b) and before the step (2c), after the step(2c) and before the step (2d), after the step (2d) and before the step(2e), after the step (2e) and before the step (2f), or after the step(2f) and before the step (2g).

The treatment may be performed during the step (2a), (2b), (2c), (2d),(2e), (2f), or (2g). The treatment may be performed multiple times. Theheat treatment and the fluorination treatment may be performed incombination, and may be performed simultaneously.

The above method can provide a stretched article.

The extrusion aid used may be, but is not limited to, commonly knownone. An example thereof is hydrocarbon oil.

The molded article may also be obtained by a production method includingcompression-molding fluoropolymer powder. In this case, the treatmentmay be performed during the compression-molding step or after thecompression molding. The treatment may be performed multiple times. Theheat treatment and the fluorination treatment may be performed incombination.

EXAMPLES

The invention is described with reference to examples, but the inventionis not intended to be limited by these examples.

The parameters in the examples were determined by the following methods.

Volume Average Particle Size

The volume average particle size was determined by dynamic lightscattering. A fluoropolymer aqueous dispersion with the fluoropolymersolid content being adjusted to 1.0% by mass was prepared. The volumeaverage particle size was determined from 70 measurement processes usingELSZ-1000s (available from Otsuka Electronics Co., Ltd.) at 25° C. Therefractive index of the solvent (water) was 1.3328 and the viscosity ofthe solvent (water) was 0.8878 mPa·s.

Number Average Particle Size

The fluoropolymer aqueous dispersion was diluted with water to a solidcontent of 0.15% by mass. The transmittance of incident light at 550 nmrelative to the unit length of the resulting diluted latex wasdetermined and the number-based length average particle size wasdetermined by measuring the Feret diameter in a transmission electronmicroscope (TEM). Based on these values, a calibration curve was drawn.Using this calibration curve, the number average particle size of eachsample was determined from the measured transmittance of incident lightat 550 nm.

Melt Flow Rate (MFR)

The MFR used was the mass (g/10 min) of a polymer that flowed out of anozzle having an inner diameter of 2 mm and a length of 8 mm per 10minutes at 297° C. and a load of 5 kg in conformity with ASTM D3307-01using a melt indexer (available from Toyo Seiki Seisaku-sho, Ltd.).

Solid Content

A 1-g portion of the fluoropolymer aqueous dispersion was dried at 150°C. for 60 minutes in an air dryer. The percentage of the mass of thenon-volatile matter to the mass (1 g) of the aqueous dispersion wasexpressed by percentage, and this percentage value was used as the solidcontent.

Peak Temperature

For a PTFE resin that was obtained by polymerization and that had neverbeen heated up to 300° C. or higher, a heat-of-fusion curve of the firstheating at a temperature-increasing rate of 10° C./min using adifferential scanning calorimeter (DSC) was drawn. The temperaturecorresponding to the endothermic peak in the heat-of-fusion curve isdefined as the peak temperature of the PTFE resin. The temperaturecorresponding to the maximum value among the peak temperatures in thefirst temperature increase is defined as the first melting point of thePTFE resin.

Amount of Heat of Fusion

For a PTFE resin that was obtained by polymerization and that had neverbeen heated up to 300° C. or higher, a heat-of-fusion curve was drawn ata temperature-increasing rate of 10° C./min using a differentialscanning calorimeter (DSC). The amount of the heat of fusion wascalculated from the area of the region defined by the straight lineextending from 290° C. to 350° C. of the heat-of-fusion curve and theheat-of-fusion curve.

Standard Specific Gravity (SSG)

Using a sample molded in conformity with ASTM D4895-89, the SSG wasdetermined by the water replacement method in conformity with ASTM D792.

Amount of Specific Surfactant Containing Fluorine

The following describes the method of quantifying compounds representedby the following formulae (1) and (2).

The formula (1) is (H—(CF₂)_(m)—COO)_(p)M¹,

wherein m is 3 to 19; M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or 2.

The formula (2) is (H—(CF₂)_(n)—SO₃)_(q)M²,

wherein n is 4 to 20; M² is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and q is 1 or 2.

(Method of Quantifying Compound Represented by Formula (1))

Extraction from Powder

A 1-g portion of powder was mixed with 10 g (12.6 mL) of methanol andthe mixture was ultrasonicated for 60 minutes. The supernatant fluidcontaining the compound represented by the formula (1) was extracted.

Extraction from Aqueous Dispersion

The solid content of the aqueous dispersion was measured, and theaqueous dispersion in an amount corresponding to 0.5 g of the solid PTFEwas put into a 100-mL screw tube. Water and methanol was added theretosuch that the extraction solvent was to be 40 g (43.14 mL) having awater/methanol ratio by vol % of 50/50 including the water originallycontained in the aqueous dispersion. The system was well shaken foragglomeration. The solid was removed and the liquid phase wascentrifuged at 4000 rpm for one hour. The supernatant fluid containingthe compound represented by the formula (1) was extracted.

Quantification of Compound Represented by Formula (1) Contained inExtract

The amount of the compound represented by the formula (1) contained inthe extract was determined in perfluorooctanoic acid equivalent.

Calibration Curve of Perfluorooctanoic Acid

Five methanol standard solutions of perfluorooctanoic acid having therespective known concentrations within 1 ng/mL to 100 ng/mL wereprepared, and subjected to analysis using a liquid chromatograph-massspectrometer (LC-MS ACQUITY UPLC/TQD, available from Waters). Using thefirst order approximation from the respective sample concentrations andthe peak integral values, the values a and b were determined by thefollowing equation (1):

A=a×X+b  (1)

A: peak area of perfluorooctanoic acid

X: concentration (ng/mL) of perfluorooctanoic acid.

Structure of Measurement Device and LC-MS Measurement Conditions

TABLE 1 LC section Device Acquity UPLC, Waters Column Acquity UPLC BEHC18 1.7 mm (2.1 × 50 mm), Waters Mobile phase A CH₃CN B 20 mMCH₃COONH₄/H₂O 0 to 1.5 min A:B = 10:90 1.5 to 8.5 min A:B = 10:90 to A:B= 90:10 Linear gradient 8.5 to 10 min A:B - 90:10 Flow rate 0.4 mL/minColumn temperature 40° C. Amount of sample fed 5 μL MS section Device TQDetecter Measurement mode MRM (Multiple Reaction Monitoring) Ionizationmethod Electrospray ionization Negative mode

MRM Measurement Parameters

TABLE 2 Compound Precursor Product Perfluorooctanoic acid 413 369

Amount of C4-C20 Compound Represented by Formula (1) Contained inExtract

Using a liquid chromatograph-mass spectrometer, a C4-C20 compoundrepresented by the formula (1) was quantified. For the extracted liquidphase, the peak areas of the compounds represented by the formula (1)having the respective carbon numbers were determined by MRM.

MRM Measurement Parameters

TABLE 3 Carbon Compound name number Precursor Product (H—(CF₂)₃—COO)M  4195 131 (H—(CF₂)₄—COO)M  5 245 181 (H—(CF₂)₅—COO)M  6 295 231(H—(CF₂)₆—COO)M  7 345 281 (H—(CF₂)₇—COO)M  8 395 331 (H—(CF₂)₈—COO)M  9445 381 (H—(CF₂)₉—COO)M 10 495 431 (H—(CF₂)₁₀—COO)M 11 545 481(H—(CF₂)₁₁—COO)M 12 595 531 (H—(CF₂)₁₂—COO)M 13 645 581 (H—(CF₂)₁₃—COO)M14 695 631 (H—(CF₂)₁₄—COO)M 15 745 681 (H—(CF₂)₁₅—COO)M 16 795 731(H—(CF₂)₁₆—COO)M 17 845 781 (H—(CF₂)₁₇—COO)M 18 895 831 (H—(CF₂)₁₈—COO)M19 945 881 (H—(CF₂)₁₉—COO)M 20 995 931

The amount of the compound represented by the formula (1) containing(m+1) carbon atoms in the extract was calculated by the followingformula (3). The values a and b in the formula (3) were calculated bythe formula (1).

XCm=((ACm−b)/a)×((50×m+45)/413)  (3)

XCm: amount (ng/mL) of compound represented by formula (1) containing(m+1) carbon atoms in extract solution

ACm: peak area of compound represented by formula (1) containing (m+1)carbon atoms in extract solution

The quantification limit in this measurement is 1 ng/mL.

Amount of compound represented by formula (1) containing (m+1) carbonatoms contained in powder

The amount of the compound represented by the formula (1) containing(m+1) carbon atoms contained in the powder was determined by thefollowing formula (4).

YCm=XCm×12.6  (4)

YCm: amount (relative to fluoropolymer) of compound represented byformula (1) containing (m+1) carbon atoms contained in powder

Amount of compound represented by formula (1) containing (m+1) carbonatoms contained in aqueous dispersion

The amount of the compound represented by the formula (1) containing(m+1) carbon atoms contained in the aqueous dispersion was determined bythe following formula (5).

ZCm=XCm×86.3  (5)

ZCm: amount (relative to fluoropolymer) of compound represented byformula (1) containing (m+1) carbon atoms contained in aqueousdispersion

(Method of Quantifying Compound Represented by Formula (2))

Extraction from Powder

A 1-g portion of powder was mixed with 10 g (12.6 mL) of methanol andthe mixture was ultrasonicated for 60 minutes. The supernatant fluidcontaining the compound represented by the formula (2) was extracted.

Extraction from Aqueous Dispersion

The solid content of the aqueous dispersion was measured, and theaqueous dispersion in an amount corresponding to 0.5 g of the solid PTFEwas put into a 100-mL screw tube. Water and methanol was added theretosuch that the extraction solvent was to be 40 g (43.14 mL) having awater/methanol ratio by vol % of 50/50 including the water originallycontained in the aqueous dispersion. The system was well shaken foragglomeration. The solid was removed and the liquid phase wascentrifuged at 4000 rpm for one hour. The supernatant fluid containingthe compound represented by the formula (2) was extracted.

Quantification of Compound Represented by Formula (2) Contained inExtract

The amount of the compound represented by the formula (2) contained inthe extract was determined in perfluorooctanesulfonic acid equivalent.

Calibration Curve of Perfluorooctanesulfonic Acid

Five methanol standard solutions of perfluorooctanesulfonic acid havingthe respective known concentrations within 1 ng/mL to 100 ng/mL wereprepared, and subjected to analysis using a liquid chromatograph-massspectrometer (LC-MS ACQUITY UPLC/TQD, available from Waters). Using thefirst order approximation from the respective sample concentrations andthe peak integral values, the values a and b were determined by thefollowing equation (1):

A=a×X+b  (1)

A: peak area of perfluorooctanesulfonic acid

X: concentration (ng/mL) of perfluorooctanesulfonic acid.

Structure of Measurement Device and LC-MS Measurement Conditions

TABLE 4 LC section Device Acquity UPLC, Waters Column Acquity UPLC BEHCl 8 1.7 mm (2.1 × 50 mm), Waters Mobile phase A CH₃CN B 20 mMCH₃COONH₄/H₂O 0 to 1.5 min A:B = 10:90 1.5 to 8.5 min A:B = 10:90 to A:B= 90:10 Linear gradient 8.5 to 10 min A:B = 90:10 Flow rate 0.4 mL/minColumn temperature 40° C. Amount of sample fed 5 μL MS section Device TQDetecter Measurement mode MRM (Multiple Reaction Monitoring) Ionizationmethod Electrospray ionization Negative mode

MRM Measurement Parameters

TABLE 5 Compound Precursor Product Perfluorooctanesulfonic acid 499 99

Amount of C4-C20 compound represented by formula (2) contained inextract Using a liquid chromatograph-mass spectrometer, a C4-C20compound represented by the formula (2) was quantified. For theextracted liquid phase, the peak areas of the compounds represented bythe formula (2) having the respective carbon numbers were determined byMRM.

MRM Measurement Parameters

TABLE 6 Carbon Compound number Precursor Product (H—(CF₂)₄—SO₃)M  4 28199 (H—(CF₂)₅—SO₃)M  5 331 99 (H—(CF₂)₆—SO₃)M  6 381 99 (H—(CF₂)₇—SO₃)M 7 431 99 (H—(CF₂)₈—SO₃)M  8 481 99 (H—(CF₂)₉—SO₃)M  9 531 99(H—(CF₂)₁₀—SO₃)M 10 581 99 (H—(CF₂)₁₁—SO₃)M 11 631 99 (H—(CF₂)₁₂—SO₃)M12 681 99 (H—(CF₂)₁₃—SO₃)M 13 731 99 (H—(CF₂)₁₄—SO₃)M 14 781 99(H—(CF₂)₁₅—SO₃)M 15 831 99 (H—(CF₂)₁₆—SO₃)M 16 881 99 (H—(CF₂)₁₇—SO₃)M17 931 99 (H—(CF₂)₁₈—SO₃)M 18 981 99 (H—(CF₂)₁₉—SO₃)M 19 1031 99(H—(CF₂)₂₀—SO₃)M 20 1081 99

The amount of the compound represented by the formula (2) containing ncarbon atoms in the extract was calculated by the following formula (3).The values a and b in the formula (3) were calculated by the formula(1).

XSn=((ASn−b)/a)×((50×n+81)/499)  (3)

XSn: amount (ng/mL) of compound represented by formula (2) containing ncarbon atoms in extract solution

ASn: peak area of compound represented by formula (2) containing ncarbon atoms in extract solution

The Quantification Limit in this Measurement is 1 ng/mL.

Amount of compound represented by formula (2) containing n carbon atomscontained in powder

The amount of the compound represented by the formula (2) containing ncarbon atoms contained in the powder was determined by the followingformula (4).

YSn=XSn×12.6  (4)

YSn: amount (relative to fluoropolymer) of compound represented byformula (2) containing n carbon atoms contained in powder

Amount of compound represented by the formula (2) containing n carbonatoms contained in aqueous dispersion

The amount of the compound represented by the formula (2) containing ncarbon atoms contained in the aqueous dispersion was determined by thefollowing formula (5).

ZSn=XSn×86.3  (5)

ZSn: amount (relative to fluoropolymer) of compound represented byformula (2) containing n carbon atoms contained in aqueous dispersion

Synthesis Example 1

A mixture of 10-undecenoic acid (4.7 g), 1,4-benzoquinone (0.63 g), DMF(50 mL), water (5 mL), and PdCl₂ (0.09 g) was heated and stirred at 90°C. for 12 hours.

The solvent was then evaporated under reduced pressure. The resultingresidue was mixed with a solution of sodium methoxide in methanol andthe mixture was filtered. The solid residue was mixed with hydrochloricacid and the mixture was extracted with ethyl acetate. The extract wasdried over sodium sulfate, and the solvent was evaporated under reducedpressure. The residue was purified by column chromatography, whereby10-oxoundecanoic acid (3.2 g) was obtained.

The spectrum data of the resulting 10-oxoundecanoic acid are thefollowing.

¹H-NMR (CDCl₃) δ ppm: 1.27-1.37 (m, 8H), 1.51-1.60 (m, 4H), 2.11 (s,3H), 2.29-2.42 (m, 4H)

The resulting 10-oxoundecanoic acid (0.73 g) was added to a 2 M solutionof ammonia in methanol and water was evaporated. Thereby, ammonium10-oxoundecanoate (0.57 g) was obtained.

The spectrum data of the resulting ammonium 10-oxoundecanoate(hereinafter, referred to as a surfactant D) are the following.

¹H-NMR (CDCl₃) δ ppm: 1.05 (m, 8H), 1.31 (m, 4H), 1.96-2.02 (m, 5H),2.28-2.34 (t, J=7.3, 4H)

Example 1

A 1-L-capacity glass autoclave was charged with 550 g of deionizeddegassed water, 30 g of paraffin wax, and 0.0145 g of the surfactant D.The reactor was sealed and the system was purged with nitrogen, so thatoxygen was removed. The reactor was heated up to 70° C. and TFE wasfilled into the reactor such that the reactor was adjusted to 0.78 MPa.Then, 0.110 g of ammonium persulfate (APS) serving as a polymerizationinitiator was put thereinto. TFE was fed so as to standardize thereaction pressure to 0.78 MPa. When 50 g in total of TFE was fed, thestirring was stopped and the pressure was released until the reactor wasadjusted to the atmospheric pressure. The aqueous dispersion wascollected from the reactor and cooled so that the paraffin wax wasseparated. The particles contained in the resulting PTFE aqueousdispersion had a volume average particle size of 182 nm. The solidcontent in the resulting PTFE aqueous dispersion was 8.2% by mass.

The resulting PTFE aqueous dispersion was dried at 150° C. for 18 hours.

The resulting PTFE resin was subjected to DSC analysis. The peaktemperature at the first temperature increase was observed at 334° C.The SSG was 2.260. This demonstrates that the resulting PTFE was ahigh-molecular-weight PTFE.

A 2-mL portion of the resulting PTFE aqueous dispersion was mixed with30 mL (23.8 g) of methanol, and the mixture was extracted for threehours under ultrasonic vibrations. The surfactant D was dissolved inmethanol to prepare standard solutions having a concentration of 0.1, 1,10, 100, or 1000 ppm. A calibration curve was drawn by HPLC, and thenthe surfactant contained in the extract was quantified. The amount ofthe surfactant was 24 ppm relative to the PTFE aqueous dispersion.

Synthesis Example 2

To 10-oxoundecanoic acid (1.8 g) was added 1.0 M KOH water and water wasthen evaporated, whereby potassium 10-oxoundecanoate (2.2 g) wasobtained.

The spectrum data of the resulting potassium 10-oxoundecanoate(hereinafter, referred to as a surfactant E) are the following.

¹H-NMR (CDCl₃) δ ppm: 1.04 (m, 8H), 1.30-1.32 (m, 4H), 1.89-2.01 (m,5H), 2.27-2.33 (t, J=7.6, 4H)

Example 2

A 1-L-capacity glass autoclave was charged with 550 g of deionizeddegassed water, 30 g of paraffin wax, and 0.0145 g of the surfactant E.The reactor was sealed and the system was purged with nitrogen, so thatoxygen was removed. The reactor was heated up to 70° C. and TFE wasfilled into the reactor such that the reactor was adjusted to 0.78 MPa.Then, 0.110 g of ammonium persulfate (APS) serving as a polymerizationinitiator was put thereinto. TFE was fed so as to standardize thereaction pressure to 0.78 MPa. When 50 g in total of TFE was fed, thestirring was stopped and the pressure was released until the reactor wasadjusted to the atmospheric pressure. The aqueous dispersion wascollected from the reactor and cooled so that the paraffin wax wasseparated. The particles contained in the resulting PTFE aqueousdispersion had a volume average particle size of 216 nm. The solidcontent in the resulting PTFE aqueous dispersion was 8.2% by mass.

The resulting PTFE aqueous dispersion was dried at 150° C. for 18 hours.

The resulting PTFE resin was subjected to DSC analysis. The peaktemperature at the first temperature increase was observed at 334° C.The SSG was 2.261. This demonstrates that the resulting PTFE was ahigh-molecular-weight PTFE.

The compounds represented by the formula (1) or the formula (2) in theresulting PTFE aqueous dispersion were quantified. The results are shownin the following Table 7.

A 2-mL portion of the resulting PTFE aqueous dispersion was mixed with30 mL (23.8 g) of methanol, and the mixture was extracted for threehours under ultrasonic vibrations. The surfactant E was dissolved inmethanol to prepare standard solutions having a concentration of 0.1, 1,10, 100, or 1000 ppm. A calibration curve was drawn by HPLC, and thenthe surfactant contained in the extract was quantified. The amount ofthe surfactant was 23 ppm relative to the PTFE aqueous dispersion.

TABLE 7 Compound represented (H—(CF₂)_(m)—COO)_(p)M¹ Compoundrepresented (H—(CF₂)_(n)—SO₃)_(q)M² by formula (1) m ppb (relative topolymer) by formula (2) n ppb (relative to polymer) m = 3 8.3E+04 n = 4Quantification limit or less m = 5 9.3E+04 n = 6 Quantification limit orless m = 7 6.6E+04 n = 8 Quantification limit or less m = 9 9.0E+03 n =10 Quantification limit or less m = 11 4.4E+02 n = 12 Quantificationlimit or less m = 13 1.1E+02 n = 14 Quantification limit or less m = 158.7E+01 n = 16 Quantification limit or less m = 17 1.8E+03 n = 18Quantification limit or less m = 19 1.9E+03 n = 20 Quantification limitor less Sum 2.5E+05 Sum Quantification limit or less * Aqueousdispersion obtained by polymerization was analyzed.

The peaks at which n is 5, 7, 9, 11, 13, 15, 17, or 9 and m is 4, 6, 8,10, 12, 14, 16, or 18 were equal to or below the quantification limit.

The compounds represented by the formula (1) or (2) contained in thedried powder obtained above were quantified. The results are shown inTable 8.

TABLE 8 Compound represented (H—(CF₂)_(m)—COO)_(p)M¹ Compoundrepresented (H—(CF₂)_(n)—SO₃)_(q)M² by formula (1) m ppb (relative topolymer) by formula (2) n ppb (relative to polymer) m ppb (relative topolymer) n ppb (relative to polymer) m = 3 Quantification limit or lessn = 4 Quantification limit or less m = 5 Quantification limit or less n= 6 Quantification limit or less m = 7 Quantification limit or less n =8 Quantification limit or less m = 9 Quantification limit or less n = 10Quantification limit or less m = 11 Quantification limit or less n = 12Quantification limit or less m = 13 Quantification limit or less n = 14Quantification limit or less m = 15 1.7E+01 n = 16 Quantification limitor less m= 17 3.9E+02 n = 18 Quantification limit or less m= 19 4.1E+02n = 20 Quantification limit or less * Powder obtained by agglomerationafter polymerization was analyzed.

The peaks at which n is 5, 7, 9, 11, 13, 15, 17, or 19 and m is 4, 6, 8,10, 12, 14, 16, or 18 were equal to or below the quantification limit.

The quantification limit is 86 ppb for aqueous dispersion and 13 ppb forpowder.

Example 3

A 6-L-capacity stainless steel autoclave was charged with 3600 g ofdeionized degassed water, 180 g of paraffin wax, and 0.540 g of thesurfactant E. The reactor was sealed and the system was purged withnitrogen, so that oxygen was removed. The reactor was heated up to 70°C. and TFE was filled into the reactor such that the reactor wasadjusted to 2.76 MPa. Then, 0.50 g of oxalic acid serving as apolymerization initiator was put thereinto and continual addition of apotassium permanganate aqueous solution was initiated. TFE was fed so asto standardize the reaction pressure to 2.76 MPa. The permanganateaqueous solution was continually added until the solid content ofpotassium permanganate was equivalent to 0.60 g. When 330 g in total ofTFE was fed, the stirring was stopped and the pressure was releaseduntil the reactor was adjusted to the atmospheric pressure. The aqueousdispersion was collected from the reactor and cooled so that theparaffin wax was separated. The particles contained in the resultingPTFE aqueous dispersion had a volume average particle size of 145 nm.The solid content in the resulting PTFE aqueous dispersion was 8.4% bymass.

The resulting PTFE aqueous dispersion was vigorously stirred andagglomerated until solidification. The resulting agglomerate was driedat 150° C. for 18 hours, whereby PTFE powder was obtained.

The resulting PTFE powder was subjected to DSC analysis. The peaktemperature at the first temperature increase was observed at 334° C.

The resulting PTFE powder had a SSG of 2.238.

The compounds represented by the formula (1) or (2) contained in thedried PTFE powder obtained above were quantified. The results are shownin Table 9.

TABLE 9 Compound represented (H—(CF₂)_(m)—COO)_(p)M¹ Compoundrepresented (H—(CF₂)_(n)—SO₃)_(q)M² by formula (1) m ppb (relative topolymer) by formula (2) n ppb (relative to polymer) m = 3 5.3E+01 n = 4Quantification limit or less m = 4 3.2E+01 n = 5 Quantification limit orless m = 5 5.8E+01 n = 6 Quantification limit or less m = 6 1.4E+02 n =7 Quantification limit or less m = 7 7.4E+01 n = 8 Quantification limitor less m = 8 2.6E+02 n = 9 Quantification limit or less m = 9 2.6E+02 n= 10 Quantification limit or less m = 10 1.7E+03 n = 11 Quantificationlimit or less m= 11 1.5E+03 n = 12 Quantification limit or less m = 122.1E+04 n = 13 Quantification limit or less m = 13 1.4E+04 n = 14Quantification limit or less m= 14 1.3E+05 n = 15 Quantification limitor less m = 15 2.5E+04 n = 16 Quantification limit or less m = 161.5E+05 n = 17 Quantification limit or less m= 17 2.3E+04 n = 18Quantification limit or less m= 18 1.3E+05 n = 19 Quantification limitor less m= 19 1.8E+03 n = 20 Quantification limit or less Sum 4.9E+05Sum Quantification limit or less * Powder obtained by agglomerationafter polymerization was analyzed.

The quantification limit is 13 ppb.

What is claimed is:
 1. A composition comprising a fluoropolymer andsubstantially free from a compound represented by the following formula(3):(H—(CF₂)₈—SO₃)_(q)M², wherein M² is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and q is 1 or
 2. 2. The composition according to claim 1, whereinthe compound represented by the formula (3) is in an amount of 1000 ppbor less relative to the fluoropolymer.
 3. The composition according toclaim 1, wherein the compound represented by the formula (3) is in anamount of 25 ppb or less relative to the fluoropolymer.
 4. Thecomposition according to claim 1, further comprising a compoundrepresented by the following formula (4) in an amount of 100 ppb or morerelative to the fluoropolymer, the formula (4) being(H—(CF₂)₇—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or
 2. 5. The composition according to claim 1, furthercomprising: a compound represented by the following formula (4) in anamount of 100 ppb or more relative to the fluoropolymer; and/or acompound represented by the following formula (4′) in an amount of 100ppb or more relative to the fluoropolymer, the formula (4) being(H—(CF₂)₇—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or 2, the formula (4′) being (H—(CF₂)₈—COO)_(p)M¹,wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or
 2. 6. The composition according to claim 1, further comprising acompound represented by the following formula (5) in an amount of 100ppb or more relative to the fluoropolymer, the formula (5) being(H—(CF₂)₁₃—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or
 2. 7. The composition according to claim 1, furthercomprising: a compound represented by the following formula (5) in anamount of 100 ppb or more relative to the fluoropolymer; and/or acompound represented by the following formula (5′) in an amount of 100ppb or more relative to the fluoropolymer, the formula (5) being(H—(CF₂)₁₃—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or 2, the formula (5′) being (H—(CF₂)₁₄—COO)_(p)M¹,wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or
 2. 8. The composition according to claim 1, further comprising: acompound represented by the following formula (4) in an amount of 1000ppb or less relative to the fluoropolymer; and 1% by mass or more of anonionic surfactant, the formula (4) being (H—(CF₂)₇—COO)_(p)M¹, whereinM¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containing asubstituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or
 2. 9. The composition according to claim 1, further comprising: atleast one of a compound represented by the following formula (4) or acompound represented by the following formula (4′), with the compoundrepresented by the formula (4) being in an amount of 1000 ppb or lessrelative to the fluoropolymer and with the compound represented by theformula (4′) being in an amount of 1000 ppb or less relative to thefluoropolymer; and 1% by mass or more of a nonionic surfactant, theformula (4) being (H—(CF₂)₇—COO)_(p)M¹, wherein M¹ is H, a metal atom,NR⁵ ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent; R⁵s are each H or an organic group and are thesame as or different from each other; and p is 1 or 2, the formula (4′)being (H—(CF₂)₈—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄,imidazolium optionally containing a substituent, pyridinium optionallycontaining a substituent, or phosphonium optionally containing asubstituent; R⁵s are each H or an organic group and are the same as ordifferent from each other; and p is 1 or
 2. 10. The compositionaccording to claim 1, further comprising: a compound represented by thefollowing formula (5) in an amount of 1000 ppb or less relative to thefluoropolymer; and 1% by mass or more of a nonionic surfactant, theformula (5) being (H—(CF₂)₁₃—COO)_(p)M¹, wherein M¹ is H, a metal atom,NR⁵ ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent; R⁵s are each H or an organic group and are thesame as or different from each other; and p is 1 or
 2. 11. Thecomposition according to claim 1, further comprising: at least one of acompound represented by the following formula (5) or a compoundrepresented by the following formula (5′), with the compound representedby the formula (5) being in an amount of 1000 ppb or less relative tothe fluoropolymer and with the compound represented by the formula (5′)being in an amount of 1000 ppb or less relative to the fluoropolymer;and 1% by mass or more of a nonionic surfactant, the formula (5) being(H—(CF₂)₁₃—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or 2, the formula (5′) being (H—(CF₂)₁₄—COO)_(p)M¹,wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or
 2. 12. The composition according to claim 1, wherein thecomposition is in the form of an aqueous dispersion.
 13. The compositionaccording to claim 1, further comprising a compound represented by thefollowing formula (4) in an amount of 1000 ppb or less relative to thefluoropolymer, the formula (4) being (H—(CF₂)₇—COO)_(p)M¹, wherein M¹ isH, a metal atom, NR⁵ ₄, imidazolium optionally containing a substituent,pyridinium optionally containing a substituent, or phosphoniumoptionally containing a substituent; R⁵s are each H or an organic groupand are the same as or different from each other; and p is 1 or
 2. 14.The composition according to claim 1, further comprising at least one ofa compound represented by the following formula (4) or a compoundrepresented by the following formula (4′), with the compound representedby the formula (4) being in an amount of 1000 ppb or less relative tothe fluoropolymer and with the compound represented by the formula (4′)being in an amount of 1000 ppb or less relative to the fluoropolymer,the formula (4) being (H—(CF₂)₇—COO)_(p)M¹, wherein M¹ is H, a metalatom, NR⁵ ₄, imidazolium optionally containing a substituent, pyridiniumoptionally containing a substituent, or phosphonium optionallycontaining a substituent; R⁵s are each H or an organic group and are thesame as or different from each other; and p is 1 or 2, the formula (4′)being (H—(CF₂)₈—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄,imidazolium optionally containing a substituent, pyridinium optionallycontaining a substituent, or phosphonium optionally containing asubstituent; R⁵s are each H or an organic group and are the same as ordifferent from each other; and p is 1 or
 2. 15. The compositionaccording to claim 1, further comprising a compound represented by thefollowing formula (5) in an amount of 1000 ppb or less relative to thefluoropolymer, the formula (5) being (H—(CF₂)₁₃—COO)_(p)M¹, wherein M¹is H, a metal atom, NR⁵ ₄, imidazolium optionally containing asubstituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or
 2. 16. The composition according to claim 1, further comprising atleast one of a compound represented by the following formula (5) or acompound represented by the following formula (5′), with the compoundrepresented by the formula (5) being in an amount of 1000 ppb or lessrelative to the fluoropolymer and with the compound represented by theformula (5′) being in an amount of 1000 ppb or less relative to thefluoropolymer, the formula (5) being (H—(CF₂)₁₃—COO)_(p)M¹, wherein M¹is H, a metal atom, NR⁵ ₄, imidazolium optionally containing asubstituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or 2, the formula (5′) being (H—(CF₂)₁₄—COO)_(p)M¹, wherein M¹ is H, ametal atom, NR⁵ ₄, imidazolium optionally containing a substituent,pyridinium optionally containing a substituent, or phosphoniumoptionally containing a substituent; R⁵s are each H or an organic groupand are the same as or different from each other; and p is 1 or
 2. 17.The composition according to claim 1, further comprising a compoundrepresented by the following formula (4) in an amount of 100 ppb or lessrelative to the fluoropolymer, the formula (4) being(H—(CF₂)₇—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or
 2. 18. The composition according to claim 1,further comprising at least one of a compound represented by thefollowing formula (4) or a compound represented by the following formula(4′), with the compound represented by the formula (4) being in anamount of 100 ppb or less relative to the fluoropolymer and with thecompound represented by the formula (4′) being in an amount of 100 ppbor less relative to the fluoropolymer, the formula (4) being(H—(CF₂)₇—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or 2, the formula (4′) being (H—(CF₂)₈—COO)_(p)M¹,wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or
 2. 19. The composition according to claim 1, further comprising acompound represented by the following formula (5) in an amount of 100ppb or less relative to the fluoropolymer, the formula (5) being(H—(CF₂)₁₃—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or
 2. 20. The composition according to claim 1,further comprising at least one of a compound represented by thefollowing formula (5) or a compound represented by the following formula(5′), with the compound represented by the formula (5) being in anamount of 100 ppb or less relative to the fluoropolymer and with thecompound represented by the formula (5′) being in an amount of 100 ppbor less relative to the fluoropolymer, the formula (5) being(H—(CF₂)₁₃—COO)_(p)M¹, wherein M¹ is H, a metal atom, NR⁵ ₄, imidazoliumoptionally containing a substituent, pyridinium optionally containing asubstituent, or phosphonium optionally containing a substituent; R⁵s areeach H or an organic group and are the same as or different from eachother; and p is 1 or 2, the formula (5′) being (H—(CF₂)₁₄—COO)_(p)M¹,wherein M¹ is H, a metal atom, NR⁵ ₄, imidazolium optionally containinga substituent, pyridinium optionally containing a substituent, orphosphonium optionally containing a substituent; R⁵s are each H or anorganic group and are the same as or different from each other; and p is1 or
 2. 21. The composition according to claim 1, wherein thefluoropolymer is obtained by polymerization using a hydrocarbon-basedsurfactant.
 22. The composition according to claim 13, wherein thecomposition is in the form of powder.
 23. The composition according toclaim 22, wherein the composition has a tone L* of 50 or lower afterfiring and before a fluorine treatment.
 24. The composition according toclaim 22, wherein the composition exhibits a tone change ΔL* of 70% orhigher before and after a fluorination treatment.